Quiz
Inferential Statistics for Data Science
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Perguntas do quiz (50)
1Select the right answer.
With the help of inferential statistics, we can :- AMaking conclusions from a sample about the population
- BConclude if a sample selected is statistically significant to the whole population or not
- CCompare two models to find which one is more statistically significant as compared to the other.
- DWe can do feature selection, whether adding or removing a variable helps in improving the model or not.
- EHypothesis testing.
- FAll
2Standard Error is the amount of variation in the _________ data. It is related to Standard Deviation as σ/√n, where, n is the _________ size.
- ASample
- BPopulation
3A Sampling Distribution is a probability distribution of a statistic (Mean/Median/Mode) obtained through a large number of samples drawn from a specific population.
- ATrue
- BFalse
4A Sampling Distribution behaves much like a normal curve and has some interesting properties like :
- AThe shape of the Sampling Distribution does not reveal anything about the shape of the population.
- BSampling Distribution helps to estimate the population statistic.
- CBoth.
5Central Limit Theorem states that:
When plotting a sampling distribution of means, the mean of sample means will be equal to the population mean. And the sampling distribution will approach a normal distribution with variance equal to σ/√n where σ is the standard deviation of population and n is the sample size.- AFalse
- BTrue
6Greater the sample size, lower the standard error and greater the accuracy in determining the population mean from the sample mean?
- AFalse
- BTrue
7No matter the shape of the population distribution, be it bi-modal, right-skewed, etc. The shape of the Sampling Distribution will remain the same (normal curve)?
- ATrue
- BFalse
8For a sampling distribution:
The number of samples has to be sufficient (generally more than 50) to satisfactorily achieve a normal curve distribution. We also have to keep the sample size fixed since any change in sample size will change the shape of the sampling distribution and it will no longer be bell-shaped?- AFalse
- BTrue
9As we increase the sample size, the sampling distribution squeezes from both sides giving a better estimate of the population statistic since it lies somewhere in the middle of the sampling distribution (generally).
- AFalse
- BTrue
10The confidence interval is a type of interval estimate from the ___________ distribution which gives a range of values in which the population statistic may lie.
- ASampling
- BPopulation
11The margin of error is a statistic expressing the amount of random sampling error in the results of a survey.
- ATrue
- BFalse
12Margin of Error________ the width of Confidence Interval
- A1/2
- B1/4th
13Which of the following points are true for confidence intervals?
- AConfidence Intervals can be built with different degrees of confidence suitable to a user’s needs like 70 %, 90% etc.
- BGreater the sample size, smaller the Confidence Interval
- CThere are different confidence intervals for different sample means. For example, a sample mean of 40 will have a different confidence interval from a sample mean of 45.
- D95% Confidence Interval, does not mean that the probability of a population mean to lie in an interval is 95%. Instead, 95% C.I means that 95% of the Interval estimates will contain the population statistic.
- EAll of the above.
14Hypothesis testing lets us identify ________ statistic to be checked against a _________ statistic or statistic of another sample to study any intervention etc.
- ASample, Population
- BPopulation, Sample
15Null hypothesis is a type of hypothesis in which we assume that sample observations are not by chance. They are affected by some non-random situation. It is denoted by H1 or Ha.
- ATrue
- BFalse
16Alternate Hypothesis is a type of hypothesis in which we assume that the sample observations are purely by chance. It is denoted by H0.
- ATrue
- BFalse
17Hypothesis Testing is done on different levels of confidence and makes use of z-score to calculate the probability.
- AFalse
- BTrue
18For a 95% Confidence Interval, anything above the z-threshold for 95% would reject the null hypothesis.
- AFalse
- BTrue
19Write down the steps to hypothesis testing.
- Awrite your answer down.
- Bcheck them later after the quiz.
20The significance level, also denoted as alpha or α, is the probability of rejecting the null hypothesis when it is ________.
- ATrue
- BFalse
21p-value is the probability of obtaining results at least as extreme as the observed results of a statistical hypothesis test, assuming that the null hypothesis is correct.
- ATrue
- BFalse
22Low enough p-value is ground for rejecting the null hypothesis. We reject the null hypothesis if the p-value is less than the significance level?
- AFalse
- BTrue
23Type-1 error: Type 1 error is the case when we fail to reject the null hypothesis but actually it is false. The probability of having a type-1 error is called beta(β).
- AFalse
- BTrue
24Type-2 error: Type 2 error is the case when we reject the null hypothesis but in actual it was true. The probability of having a Type-2 error is called significance level alpha(α).
- ATrue
- BFalse
25For Type 1 and Type 2 error:
α= P (Null hypothesis rejected | Null hypothesis is true)
β= P (Null hypothesis accepted | Null hypothesis is false)- ATrue
- BFalse
26Power of test is defined as
P= 1- Type-2 error
= 1 – β
Lesser the type-2 error more the power of the hypothesis test.- ATrue
- BFalse
27For a Z - test:
1. A Z-test is mainly used when the data is normally distributed.
2. We find the Z-statistic of the sample means and calculate the z-score.
3. Z-test is mainly used when the population mean and standard deviation are given.
- ATrue
- BFalse
28T-tests are similar to the z-scores, the only difference being that instead of the Population Standard Deviation, we use the Sample Standard Deviation?
- ATrue
- BFalse
29Z-tests are statistical calculations that can be used to compare population means to a sample's.
T-tests are calculations used to test a hypothesis, but they are most useful when we need to determine if there is a statistically significant difference between two independent sample groups.- ATrue
- BFalse
30The Degree of Freedom is the number of __________that have the choice of having more than one arbitrary value.
- AVariable
- BSample
31Select the True statement
- A1. Greater the difference between the sample mean and the population mean, greater the chance of rejecting the Null Hypothesis.
- B2. Greater the sample size, greater the chance of rejection of Null Hypothesis.
- CBoth
32One-sample t-test compares the mean of _________ data to a known value.
- ASample
- BPopulation
33Which of the following points are true for One Sample T- test?
- ADetermine whether the mean of a group differs from the specified value.
- BCalculate a range of values that are likely to include the population mean.
- CWe can run a one-sample T-test when we do not have the population S.D. or we have a sample of size less than 30.
- DAll of them.
34We use a two-sample T-test when we want to evaluate whether the mean of the two independent samples is different or not.
- AFalse
- BTrue
35Two-sample T-test is used to:
- ADetermine whether the means of two independent groups differ.
- BCalculate a range of values that is likely to include the difference between the population means.
- CBoth
36Points to be noted for two sample T-test are:
1. The groups to be tested should be __________
2. The groups’ distribution should not be highly _________.- AIndependent, Skewed
- BDependent, Normal
37A Independent Samples t-test compare the means for ______ different groups?
Samples are __________ of each other?- ATwo, Independent
- BSame, Dependent
38A Paired sample t-test compares means from the ______ group at different times?
Samples are _________ on each other?- ASame, Dependent
- BTwo, Independent
39 ANOVA is used to determine whether there are any statistically significant differences between the means of ________ independent (unrelated) groups.
- AOne
- BTwo
- CThree or more
40 A one-way ANOVA has ______ independent variable, while a two-way ANOVA has ______.
- AOne, Two
- BTwo, One
41Write down the steps to perform ANOVA.
- AWrite down the answers
- BCheck them later
42Practical applications of ANOVA in modeling are:
- AIdentifying whether a categorical variable is relevant to a continuous variable.
- BIdentifying whether a treatment was effective to the model or not.
- CBoth.
43The Chi-Square Test determines whether there is an association between _______ variables (i.e., whether the variables are independent or related).
- ACategorical
- BContinuous
44Goodness of fit: It compares two categorical variables to find whether they are related with each other or not.
- ATrue
- BFalse
45Test of Independence: It determines if sample data of categorical variables matches with population or not.
- ATrue
- BFalse
46Regression analysis is a form of predictive modelling technique which investigates the relationship between a ___________ (target) and __________ variable (s) (predictor).
- ADependent, Independent
- BIndependent, Dependent
47The regression sum of squares describes how well a regression model represents the modeled data.
A higher regression sum of squares indicates that the model does not fit the data well?- ATrue
- BFalse
48A residual sum of squares (RSS) is a statistical technique used to measure the amount of_________ in a data set that is not explained by a regression model.
- AMean
- BVariance
49Coefficient of Determination (R-Square): It represents the strength of correlation between two variables?
- ATrue
- BFalse
50Correlation Coefficients are used to measure how strong a relationship is between two variables?
- ATrue
- BFalse
Informações
- Descrição
- A basic quiz on Inferential Statistics.
- Autor
- Vishakha Achmare
- Idioma
- English
- Visualizações
- 78
- Etiquetas
- Avaliação
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