1798072
Questão 1
Questão
We should determine our objectives
of a study before we collect the data.
Responda
- True
- False
Questão 2
Questão
The numbers on a basketball jersey
are an example of qualitative data.
Responda
- True
- False
Questão 3
Questão
A cumulative relative frequency
totals to
Responda
-
0%
-
100%
-
The total number in your sample (n)
-
Cannot be determined without seeing the data
Questão 4
Questão
A data set that is skewed left
(negative) has most of the data
values on the left with a few data
values trailing off to the right.
Responda
- True
- False
Questão 5
Questão
A descriptive measure of a sample is
a parameter.
Responda
- True
- False
Questão 6
Questão
A stem and leaf plot is useful
because it
Responda
-
shows the distribution of the data
-
contains all the original data values
-
shows the distribution of the data AND contains all the original data values
-
it is a cumulative distribution
Questão 7
Questão
The first quartile of a distribution can
never be less than zero.
Responda
- True
- False
Questão 8
Questão
A boxplot is a good way to show the
mean of a data set.
Responda
- True
- False
Questão 9
Questão
Generally speaking, a stem and leaf
plot cannot be constructed from a
boxplot, but a boxplot can be
constructed from a stem and leaf
plot.
Responda
- True
- False
Questão 10
Questão
A population consists of the numbers 3,
8, 4. The mean and median, respectively,
are:
Responda
-
5,8
-
3,8
-
4,5
-
5,4
Questão 11
Questão
The median and mode are not
affected by outlier values.
Responda
- True
- False
Questão 12
Questão
Every data set has a mode.
Responda
- True
- False
Questão 13
Questão
One section of SCM 200 has 20 students,
another has 25 students, and a third
section has 55 students. A weighted
average of the number of students in
these sections is:
Responda
-
25
-
40.5
-
33-1/3
-
30
Questão 14
Questão
The following measures of variation
measure distance from the mean:
Responda
-
mean absolute deviation
-
variance
-
interquartile range
-
mean absolute deviation AND variance
Questão 15
Questão
Median is a measure of variability of
a data set.
Responda
- True
- False
Questão 16
Questão
Range is sensitive to all data values.
Responda
- True
- False
Questão 17
Questão
If we want the average of all the
deviations from the mean of a data
set, we can simply add the deviations
and divide by n.
Responda
- True
- False
Questão 18
Questão
The mean absolute deviation of the four
numbers 6, 14, 14, 14 is equal to
Responda
-
0
-
1
-
2
-
3
Questão 19
Questão
The units of a population mean absolute
deviation for a problem in which the units
are feet are
Responda
-
feet squared
-
the absolute value of feet
-
feet
-
no units. MAD is a relative measure
Questão 20
Questão
A population has three values: 3, 7, 5.
Find the population variance.
Responda
-
0
-
2.67
-
1.63
-
4
-
2
Questão 21
Questão
A population consisted of the values 3, 7,
11, 11, 13. The population standard
deviation is equal to:
Responda
-
12.8
-
3.58
-
16
-
4
Questão 22
Questão
A sample consisting of the numbers 3, 6,
9 has a sample variance equal to 12.
Responda
- True
- False
Questão 23
Questão
The number of hours a child spent
watching TV over the past three days
was 15, 3, 9. Compute the sample
standard deviation.
Responda
-
24
-
6
-
3
-
2
Questão 24
Questão
A standard deviation can sometimes be
larger in numerical value than a variance.
Responda
- True
- False
Questão 25
Questão
The coefficient of variation computed
from the three sample values 25, 30, 35
would be equal to 20.
Responda
- True
- False
Questão 26
Questão
95% of data values that conform to a bellshaped
distribution lie within how many
standard deviations of the mean?
Responda
-
0
-
1
-
2
-
3
Questão 27
Questão
Student score = 70
Class mean = 80
Standard deviation = 5
The standard score is equal to 2.
Responda
- True
- False
Questão 28
Questão
Drawing an ace of spades and a three
of hearts are complementary events.
Responda
- True
- False
Questão 29
Questão
The items in a sample space must be
Responda
-
complementary
-
exhaustive
-
random
-
complementary AND exhaustive
Questão 30
Questão
When a probability is described in terms of the proportion of times that and event can be theoretically expected to occur, it is an example of relative frequency probability.
Responda
- True
- False
Questão 31
Questão
A couple plans to have 3 children. Assuming male-female births are equally likely, what is the probability that couple will have at least one girl among the three children?
Responda
-
1/3
-
2/3
-
3/8
-
7/8
Questão 32
Questão
When one throws a die 1,000 times
and determines that the probability of
obtaining a six on a die is one-sixth,
that person has used the theoretical
approach to probability.
Responda
- True
- False
Questão 33
Questão
A student has three pairs of socks in her
closet: one black pair, one red pair, and
one white pair. If she randomly selects
two socks from her closet, what is the
probability that they will be the same
color? (i.e. They will be a matching pair.)
Responda
-
2/3
-
.20
-
.80
-
.75
Questão 34
Questão
The distribution of people’s heights
is an example of a discrete
probability distribution.
Responda
- True
- False
Questão 35
Questão
The sum of the probabilities in a
discrete probability distribution could
total 1.2.
Responda
- True
- False
Questão 36
Questão
Probabilities associated with random
variables must all be equal.
Responda
- True
- False
Questão 37
Questão
A quiz with 10 questions on it was given
to a class of 10 students. Each question
was worth one point and the results are
summarized below:
X = number of correct answers = 10, 9, 8,
7, 6, 5 or less, with frequencies f(X) = 3, 2,
1, 2, 2, 0 respectively.
The quiz score mean (expected value) is:
Responda
-
8
-
8.2
-
9
-
7.8
Questão 38
Questão
Find the variance of X for the following
probability distribution:
X P(X)
1 .4
3 .2
5 .4
Responda
-
1.6
-
4
-
8/3
-
3.2
Questão 39
Questão
Find the standard deviation of X for the
following probability distribution:
X P(X)
20 .50
30 .10
60 .40
Responda
-
4.29
-
18.4
-
19
-
361
Questão 40
Questão
Non-random samples involve
unequal probabilities.
Responda
- True
- False
Questão 41
Questão
For a random variable X to have a
binomial distribution, it is necessary that:
Responda
-
X represents the number of successes
-
the outcome of each trial is a success
-
the n trials are statistically dependent on eachother
-
X represents the number of successes AND the outcome of each trial is a success
Questão 42
Questão
A success in a binomial distribution
indicates that something positive has
occurred.
Responda
- True
- False
Questão 43
Questão
A weighted die is thrown. Success is
defined as getting an even number.
The probability of success is .55.
The probability of getting 2 even
numbers when throwing the die four
times is approximately .3675.
Responda
- True
- False
Questão 44
Questão
Samantha calls on 10 houses per day
selling Girl Scout cookies. Historically,
3 out of 4 customers buy cookies.
Assuming the binomial distribution
applies here, the variance of this
distribution is:
Responda
-
1.875
-
1.37
-
7.5
-
2.5
Questão 45
Questão
The standard deviation of the
distribution in the previous problem
is 1.37.
Responda
- True
- False
Questão 46
Questão
The standard normal distribution has
a mean of 1 and a standard deviation
of 0.
Responda
- True
- False
Questão 47
Questão
If X is a normal random variable with
a mean of 10 and a standard
deviation of 1/2, then X = 14 is 8
standard deviations away from the
mean.
Responda
- True
- False
Questão 48
Questão
Use the standard normal curve to
determine the probability that the random
variable z will fall between –0.04 and 0.44.
That is, find the following probability:
P(–0.04 < z < 0.44):
Responda
-
.4000
-
.4800
-
.1860
-
.1540
Questão 49
Questão
In the standard normal z-distribution,
the probability between z = –1 and z =
+1 is the same as the probability
between z = –0.5 and z = +1.5.
Responda
- True
- False
Questão 50
Questão
The lifetime of tires is normally distributed
with a mean of 50,000 miles and a standard
deviation of 3,000 miles. The warranty is
for 46,000 miles. What proportion of the
tires will fail after the warranty but before
52,000 miles? Indicate the interval below
that contains this probability.
Responda
-
.0000 to .2000
-
.2001 to .4000
-
.6001 to .8000
-
.8001 to 1.000
-
.4001 to .6000
Questão 51
Questão
When 6.3% of the data values fall
below a normally distributed random
variable, the correct z-value is -1.53.
Responda
- True
- False
Questão 52
Questão
Weights of cereal boxes are normally
distributed with a mean of 15 oz. and a
standard deviation of .5 oz. What is the
minimum weight a box could be and
remain in the top 14.46% of all boxes
filled?
Responda
-
16.10 oz.
-
14.47 oz.
-
15.53 oz.
-
The answer cannot be determined with the information given
Questão 53
Questão
An unbiased estimator is:
Responda
-
no more likely to be above the population parameter than below.
-
always better than a biased estimator.
-
is a specific observed value of a statistic.
-
always better than a biased estimator AND is a specific observed value of a statistic.
Questão 54
Questão
The sample range is generally an
unbiased estimator of the population
range.
Responda
- True
- False
Questão 55
Questão
A disadvantage of a point estimate is
that we don’t know how accurate that
estimate is.
Responda
- True
- False
Questão 56
Questão
A sampling distribution is a
distribution of all possible values of a
statistic for a given sample size.
Responda
- True
- False
Questão 57
Questão
All standard deviations are standard
errors, but not all standard errors are
standard deviations.
Responda
- True
- False
Questão 58
Questão
If a random sample of size 16 is taken
from a skewed population whose mean is
equal to 360 and standard deviation is 36,
the standard error of the mean would
equal:
Responda
-
9
-
90
-
10
-
1/9
Questão 59
Questão
Given a population standard
deviation, as sample size increases,
standard error also increases.
Responda
- True
- False
Questão 60
Questão
For a test, the pop. mean score is 1100 and
the pop. st. dev. is 100. If the test is given
to 36 randomly selected individuals, what
is the probability that the sample mean will
lie between 1090 and 1122? After finding
the appropriate probability, indicate the
interval that includes this probability:
Responda
-
.0000 to .3000
-
.8501 to 1.000
-
.6001 to .7000
-
.3001 to .6000
-
.7001 to .8500
Questão 61
Questão
The Central Limit Theorem assures
us that the sampling distribution for
the sample mean approaches a
normal distribution as the sample
size increases, regardless of the
shape of the population distribution.
Responda
- True
- False
Questão 62
Questão
Records have shown that 15% of patients
are not satisfied with their care. A poll of
100 patients was conducted. What is the
probability that more than 18 patients will
not be satisfied with their care? After
finding the probability, indicate the
interval that includes this probability.
Responda
-
.0000 to .3000
-
.8501 to 1.000
-
.6001 to .7000
-
.3001 to .6000
-
.7001 to .8500
Questão 63
Questão
Confidence intervals specify
parameter values in advance.
Responda
- True
- False
Questão 64
Questão
In using the standard normal distribution
to establish a confidence interval for the
average number of hours that a light bulb
will last, what is the appropriate z-value to
use for a 34% level of confidence:
Responda
-
0.17
-
0.1331
-
0.44
-
0.99
Questão 65
Questão
Other things being equal, a 90%
confidence interval is wider than a
95% confidence interval.
Responda
- True
- False
Questão 66
Questão
A bank wants to determine mean waiting
time. It samples 100 customers and the
mean time is 6.9 minutes. Population
standard deviation is assumed to be 4
minutes. Find a 91.98% confidence
interval of mean waiting time:
Responda
-
6.9 +/- 0.7
-
6.9 +/- 0.92
-
6.9 +/- 0.5
-
6.9 +/- 1.75
Questão 67
Questão
A t-distribution with 5 degrees of
freedom has less area in the tails
than a standard normal distribution.
Responda
- True
- False
Questão 68
Questão
The following is true about the t-distribution:
Responda
-
like the standard normal distribution, there is only one t-distribution
-
the mean is 0
-
is determined by the parameter mu
-
approaches the standard normal as degrees of freedom become smaller
Questão 69
Questão
The important distinction between
the z-statistic and t-statistic is that z
is used for large sample sizes and t is
used for small sample sizes.
Responda
- True
- False
Questão 70
Questão
A confidence interval for a true population
mean is to be constructed from sample
data with size n = 23. The t-value to use
for setting a 90% level of confidence is:
Responda
-
1.321
-
1.319
-
1.717
-
1.714
-
1.645
Questão 71
Questão
A random sample of 4 glass rods is tested
and reveals the following breaking
strength in pounds: 8, 4, 2, 6. Construct
an 80% confidence interval for the true
mean breaking strength:
Responda
-
(1.73, 8.27)
-
(3.74, 6.26)
-
(-.46, 10.46)
-
(2.89, 7.11)
Questão 72
Questão
Increasing the sample size, but using
the same level of confidence,
produces a confidence interval that
has a greater likelihood of containing
the parameter being estimated.
Responda
- True
- False
Questão 73
Questão
The mean age of viewers of TV shows
interests advertisers. A major network
believes that the mean age of viewers of a
show is more than 30. Many affiliate
stations claim the mean age is not greater
than 30. What is H0 for testing the major
network’s claim. Population mean mu is:
Responda
-
less than 30
-
greater than 30
-
not equal to 30
-
at least 30
-
at most 30
Questão 74
Questão
In testing the hypothesis below, a
statistician found that z = -0.44. What is
the p-value?
H0: mu = 10
Ha: mu does not equal 10
Responda
-
.67
-
.66
-
.56
-
.33
-
.17
Questão 75
Questão
In order to compute the p-value from
sample data, we need to know both
the alternative hypothesis and the
level of significance.
Responda
- True
- False
Questão 76
Questão
To test that the mean lifetime of light
bulbs is at least 900 hours (pop. normally
distributed and pop. st. dev. is 20), a
random sample of 25 bulbs is tested,
yielding a sample mean of 894 hours.
Find the p-value for the test. Indicate
which interval below contains the p-value.
Responda
-
.0301 to .1000
-
.5001 to 1.000
-
.2001 to .5000
-
.0000 to .0300
-
.1001 to .2000
Questão 77
Questão
If the p-value for a given hypothesis
testing problem is .055 and the level
of significance is .05, the null
hypothesis should be rejected.
Responda
- True
- False
Questão 78
Questão
In the following hypothesis test,
H0: mu = 4
Ha: mu > 4
the t-value was computed to be –2
and degrees of freedom are 11. The
correct p-value is .025 < p-value < .05.
Responda
- True
- False
Questão 79
Questão
Given an upper-tailed t-test for one
mean with 30 degrees of freedom and
the value of the test statistic computed
from the sample data t = 2.75 would
yield a p-value equal to .01.
Responda
- True
- False
Questão 80
Questão
Four runners were randomly sampled and
it was found they ran 23, 19, 23, and 23
miles per week. If we wish to test the
claim that the population mean running
distance is less than 25 miles per week,
what conclusion should be reached at the
1% level of significance?
Responda
-
Reject the claim by rejecting Ho
-
Accept the claim by rejecting Ho
-
Reject the claim by accepting Ho
-
Accept the claim by accepting Ho
Questão 81
Questão
In statistical process control, if the pvalue
is less than or equal to alpha, we
should conclude the process is under
control.
Responda
- True
- False
Questão 82
Questão
If mu = 40 pounds, sigma = 4 pounds, and
sample size is 36, the LCL and UCL on a
control chart for x would be:
Responda
-
38 pounds, 42 pounds
-
28 pounds, 52 pounds
-
38.67 pounds, 41.33 pounds
-
35 pounds, 45 pounds
Questão 83
Questão
A poll in a senatorial contest revealed that
40 out of 400 randomly selected people
indicated a preference for candidate A.
Find a 95.44% confidence interval for the
proportion of voters who favor candidate
A.
Responda
-
.07 to .13
-
.06 to .14
-
.05 to .15
-
.09 to .11
-
.38 to .42
Questão 84
Questão
A promoter is deciding whether to book a
new band. The promoter decides to do a
survey to try to estimate the true
proportion of individuals in the area who
will attend the concert. What should
sample size be to estimate the proportion
to within 5% with a 68.26% confidence
level? (Assume maximum error possible.)
Responda
-
25
-
100
-
400
-
200
Questão 85
Questão
In selecting a sample size to estimate
a population proportion, the sample
size will depend, among other things,
upon the level of confidence that is to
be used for the estimate.
Responda
- True
- False
Questão 86
Questão
A company is planning to test whether the
market share of a new product during its
first year on the market is more than 20
percent. The appropriate null hypothesis
would be that the market share percentage
is
Responda
-
greater than 20%
-
less than or equal to 20%
-
less than 20%
-
not equal to 20%
-
greater than or equal to 20%
Questão 87
Questão
A manufacturer claims that no more than
20% of all units will experience a failure
within the first 5 years. 100 purchasers
randomly selected were asked to report
failures. If 28 failures were reported, what
conclusion should be reached about the
manufacturer’s claim? alpha = 5%.
Responda
-
Accept the claim by rejecting Ho
-
Reject the claim by rejecting Ho
-
Accept the claim by accepting Ho
-
Reject the claim by accepting Ho
Questão 88
Questão
Assume for a given hypothesis testing
problem, the test statistic was computed
and led to a rejection of the null at alpha of
.01. Based on this information, we can
further conclude that since H0 was rejected
at the 1% level, then H0
Responda
-
Must be rejected at alpha of 10%
-
must be accepted at alpha of 10%
-
must be accepted at alpha of 5%
-
must be accepted at alpha of 5% and 10%
Questão 89
Questão
The t-test for n1 = 15 and n2 = 15 using
paired testing has
Responda
-
14 degrees of freedom
-
13 degrees of freedom
-
29 degrees of freedom
-
28 degrees of freedom
-
30 degrees of freedom
Questão 90
Questão
A paired difference experiment produced
the following data: n = 30, xbar1 = 72, xbar2 = 75.5,
Dbar = -3.5, and SD squared = 17. SE(Dbar) is equal to:
Responda
-
-0.64
-
0.64
-
0.75
-
-0.75
-
3.10
Questão 91
Questão
Assume a matched pairs test for a
mean difference with a two-tailed
alternative hypothesis and the
number of paired differences n = 4. If
the computed test statistic t = 2.353,
then the p-value would be equal to
.05.
Responda
- True
- False
Questão 92
Questão
An analyst is testing a new system to see if
it uses a different processing time than the
old system. The time for each in seconds
was recorded for 28 samples.
Old System: mean = 21.2, s = 3.2, n = 28
New System: mean = 24.3, s = 2.1, n = 28
Difference (Old – New): mean = – 3.1,
s = 1.4, n = 28
What is the appropriate statistical test?
Responda
-
Paired t-test for mean differences
-
Hypothesis test for one proportion
-
regression analysis
-
Independent t-test for mean differences
Questão 93
Questão
An analyst is testing a new system to see if
it uses a different processing time than the
old system. The time for each in seconds
was recorded for 28 samples.
Old System: mean = 21.2, s = 3.2, n = 28
New System: mean = 24.3, s = 2.1, n = 28
Difference (Old – New): mean = – 3.1,
s = 1.4, n = 28
What is the alternative hypothesis for the
question above?
Responda
-
Ha: muD = 0
-
Ha: MuD < 0
-
Ha: MuD > 0
-
Ha: MuD does not equal 0
Questão 94
Questão
In a simple linear regression analysis,
the p-value associated with a test of
the slope coefficient was equal to .026,
which would lead us to conclude that a
linear relationship exists between the
two variables at the 5% level of
significance.
Responda
- True
- False
Questão 95
Questão
An analyst is testing a new system to see if
it uses a different processing time than the
old system. The time for each in seconds
was recorded for 28 samples.
Old System: mean = 21.2, s = 3.2, n = 28
New System: mean = 24.3, s = 2.1, n = 28
Difference (Old – New): mean = – 3.1,
s = 1.4, n = 28
The correct t-value for the previous
question is:
Responda
-
62
-
11.72
-
-62
-
-11.72
Questão 96
Questão
An analyst is testing a new system to see if
it uses a different processing time than the
old system. The time for each in seconds
was recorded for 28 samples.
Old System: mean = 21.2, s = 3.2, n = 28
New System: mean = 24.3, s = 2.1, n = 28
Difference (Old – New): mean = – 3.1,
s = 1.4, n = 28
If the p-value for this test is less than .002
and alpha is .05, analysts would conclude
that
Responda
-
the old system uses more processing time
-
the old system uses less processing time
-
the systems use the same processing time
-
the system processing times are unequal
Questão 97
Questão
A doctor claims the average person is
more than 11 pounds overweight. To test
the claim, the difference between actual
and ideal weight of 36 randomly selected
people was calculated. The sample mean
and sample standard deviation were 14
and 5 pounds respectively. At alpha of 1%,
can we conclude the claim is true?
Responda
-
Yes, the claim is true by rejecting Ho
-
Yes, the claim is true by accepting Ho
-
No, the claim is not true by rejecting Ho
-
No, the claim is not true by accepting Ho
Questão 98
Questão
The difference between the
independent sample and paired
sample approach is that with the
independent sample approach, a
background variable's effect is
controlled by pairing.
Responda
- True
- False
Questão 99
Questão
In general, the paired samples
method is preferred over the
independent samples method.
Responda
- True
- False
Questão 100
Questão
The t-test for n1 = 15 and n2 = 7 using the
independent samples approach has
(assuming equal population variances)
Responda
-
14 degrees of freedom
-
6 degrees of freedom
-
21 degrees of freedom
-
20 degrees of freedom
-
22 degrees of freedom
Questão 101
Questão
Given the following information about a
hypothesis test of the difference between
two means based on independent random
samples. (Assume normal distributions
with equal variances.) The correct pvalue
is between .005 and .01.
H0: μ1 – μ2 = 0
Ha: μ1 – μ2 ≠ 0
x1 = 16.32, x2 = 17.44,
s1squared = 4.3,
s2squared = 2.2,
n1 = 30, n2 = 32
Responda
- True
- False
Questão 102
Questão
The best statistic for pi1 - pi2 is p1 – p2.
Responda
- True
- False
Questão 103
Questão
For n1 = 70 and n2 = 100 from populations
1 and 2, the number of successes are 35
and 35 respectively. The estimate of the
difference between pi1 - pi2 is
Responda
-
0.35
-
0.15
-
0.70
-
0.50
-
0.42
Questão 104
Questão
For n1 = 200 and n2 = 100 from
populations 1 and 2, the numbers of
successes are 35 and 25 respectively.
The value of the pooled sample
proportion p-hat is 0.20.
Responda
- True
- False
Questão 105
Questão
In an upper-tailed test of the difference
of two proportions, the z-value was
calculated to be 2.69. The p-value for
this test would then be .0036.
Responda
- True
- False
Questão 106
Questão
The purpose of a scatterplot is to
visually determine if a relationship
exists between two variables.
Responda
- True
- False
Questão 107
Questão
In using the regression model for
forecasting the next value (or an
individual value) of y, the prediction
interval will be
Responda
-
the same as the estimating interval
-
narrower than the estimating interval
-
wider than the estimating interval
-
wider or narrower, depending on the data
Questão 108
Questão
The coefficient of determination (R2) is
equal to 0.64, and the linear regression
equation which indicates an inverse
relationship between x and y is equal to
ŷ = 2 - .74x, then the correlation coefficient
must necessarily be equal to:
Responda
-
-.80
-
+.64
-
-.74
-
either -.80 or +.80
Questão 109
Questão
In a simple linear regression and
correlation problem, a correlation
coefficient of .80 means that 64% of
the variation in y can be explained by
x.
Responda
- True
- False
Questão 110
Questão
When R2 = 1, then Se = Sy.
Responda
- True
- False
Questão 111
Questão
A correlation coefficient of –1.0 would
imply that the standard error of the
estimate Se would necessarily be equal
to 0.
Responda
- True
- False
Questão 112
Questão
Standard error is measured in the units
of the x variable.
Responda
- True
- False
Questão 113
Questão
The range of a regression coefficient is
– 1 to + 1.
Responda
- True
- False
Questão 114
Questão
Standard deviation of height = 2.45
inches.
Standard deviation of weight = 23
pounds.
Correlation = .56
If we are predicting weight from height,
the regression coefficient is 5.26.
Responda
- True
- False
Questão 115
Questão
If ŷ = 15 + 10x, then the estimated value of
y when x = 5 is:
Responda
-
25
-
65
-
10
-
15
-
55
Questão 116
Questão
When H0 is accepted in a regression
model, we conclude:
Responda
-
A linear relationship exists between x and y.
-
The x variable is statistically significant.
-
The x variable is not statistically significant.
-
A linear relationship exists between x and y AND the x variable is statistically significant.
Questão 117
Questão
Seasonality can be incorporated into
regression models with dummy
variables.
Responda
- True
- False
Questão 118
Questão
For the linear equation ŷ = 50 – 2x where y
is the number of items sold and x is the
price of the product in $, which is true?
Responda
-
The equation represents an inverse relationship between y and x.
-
The equation represents a positive relationship between y and x because the constant term 50 is greater than 0.
-
The slope of the line is – 2 dollars per each item sold.
-
The slope of the line is +50 dollars per each item sold.
Questão 119
Questão
If a correlation exists between y and x,
then necessarily either y causes x or x
causes y.
Responda
- True
- False
Questão 120
Questão
The advantage of multiple regression
over simple regression is that we can
change more than one variable at a
time.
Responda
- True
- False
Questão 121
Questão
If ŷ = 31 + 1.2x1 – 3.4x2 + 5x3, then the
estimated value of y when x1 = – 6, x2 = 3,
and x3 = 2 is:
Responda
-
31.7
-
25.4
-
23.6
-
38
Questão 122
Questão
The alternative hypothesis in a multiple
regression problem is that no linear
relationship exists between a given
independent variable and y.
Responda
- True
- False
Questão 123
Questão
The correlation coefficient between college
GPA and H.S. GPA is .70. The correlation
coefficient between college GPA and H.S.
rank is .60. Which of the following is true?
Responda
-
70% of the variation in college GPA can be explained by H.S. GPA.
-
60% of the variation in college GPA can be explained by H.S. GPA.
-
H.S. GPA is a better predictor of college GPA than H.S. rank.
-
There is an inverse relationship between H.S. GPA and College GPA.
Questão 124
Questão
Adding another variable to a regression
equation will make R2
Responda
-
decrease
-
increase
-
stay the same or increase
-
stay the same or decrease
-
increase, decrease, or stay the same
Questão 125
Questão
The purpose of R2 adjusted is to
discern the effect of adding a variable
to a model.
Responda
- True
- False
Questão 126
Questão
Adding another variable to a
regression equation will necessarily
make R2 adjusted increase.
Responda
- True
- False
Questão 127
Questão
It is possible for a variable to be
significant in multiple regression when
that same variable is not significant in
simple regression.
Responda
- True
- False
Questão 128
Questão
Stable environments are critical for
effective time series analysis.
Responda
- True
- False
Questão 129
Questão
Which of the following is not a component
of time series?
Responda
-
Seasonality
-
Cycle
-
Randomness
-
Trend
-
Contingency
Questão 130
Questão
The regression model based on annual
data for the last 20 years is
ŷ = 20.35 + 2.4x. The actual value of y
when x = 12 is 52. The value of the
forecasting error is:
Responda
-
68.35
-
16.35
-
2.85
-
49.15
-
40
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