Flashcards
Stats Midterm 1
Cards in this deck (39)
- 1goal of coursepredict the parameter of the pop. based on statistic of sample
- 2how you determine variablescounting (discrete)
comparison measurement (continuous) - 3Levels of Data1. Nominal - classifiable
2. Ordinal - a right/wrong way to present data, natural order
3. Interval - numbers are suggestive, ratios different, can measure distance between
4. Ratio - richest, zero is not subjective, ratio is the same - 4How to identify number of classes2 (to the power of k) > N
(k = classes, N = total number) - 5How to determine intervali ≥ h (highest #) - L (lowest #) / k
(go .1 up from the number you get) - 6Frequency (F)how many numbers are in a class
- 7Relative Frequency (RF)F / N
- 8Less than cumulative frequency (LTCF)how many are in each class including classes before it
ex. 6
10
14
15
16 - 9Relative Less than Cumulative Frequency (RLTCF)LTCF / N
- 10More than cumulative frequency (MTCF)starts with total and then progressively removes each class
ex. 16
10
6
2
1 - 11Relative More than Cumulative FrequencyMTCF / N
- 12Beauty about the averagethe sum of deviations from the mean is zero
- 13Problem with averagesensitive to outlyers, results can be skewed
- 14Mean, Median & Modemean = average
median = middle value between all the data, insensitive to outlyers
mode = max frequency (peak) - 15mean & medianmean < median, skewed to right
mean > median, skewed to left - 16rangesimplest measure of dispersion
- 17calculator steps to find average2nd
DATA
#
ENTER
Down until next x
#2
ENTER
Down etc. until end
2nd
STAT
Down - 18Deviation (d)How much the number deviates from mean (average)
- 19absolute value of deviation (|d|)d but a positive number
- 20sum ofsigma (∑)
- 21average absolute deviation (mean absolute deviation)∑ |d| / n
mathematicians dont like it so we use mean squared deviation - 22squared deviation and why we do itd²
we square to eliminate negative signs - 23mean squared deviation (VARIANCE)∑ d² / n
- 24square root of variance (STANDARD DEVIATION)√ ∑ d² / n
(de exaggerates number) - 25Box Plotdispersion around the median
- 26centre of box plotmedian, also a measure of central tendency
- 27ranges in box plotlower bound of range is before Q1
interquartile range is between Q1 and Q3
upper bound of rang is after Q3 - 28population and sample meanpopulation mean (μ) = Σ x / n (uses greek symbols)
sample mean (x̅) = Σ x / n (uses english) - 29Geometric Mean (GM)average of growth rates
- 30interest rate (r)(GM - 1) x 100
- 31population and sample variancepopulation variance (σ²) = Σ (x - µ) ² / n
sample variance (s²) = Σ (x - x̅) ² / n - 1
[(x - x̅) = d] - 32how to find variance of samplefind deviations of numbers from the mean, square each one, sum it and divide by degree of freedom
Σ (x - x̅) ² / n - 1 - 33degree of freedom (d.f)we lose one degree of freedom for every mean we know
- 34how to find frequency of median (fm)frequency x median
- 35how to get mean (x̅) of fmΣ fm / N
- 36how to get dM - x̅
- 37how to get d² how to get fd²square d
multiply d² by f - 38how to get sample variance using medianΣ fd² / n - 1
(get standard deviation by square rooting total) - 39opinion on skewingsk = 3 (mean - median / s)
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- Fall 2018 Flashcards on Stats Midterm 1, created by Lauren Wilson on 26/09/2018.
- Created by
- Lauren Wilson · Sep 2018
- Updated
- Oct 1, 2018
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