Stats quiz

Marginal distribution

Marginal = margins (totals) Relative = ratios/percentages

relative

Instead of giving you the number of people, you give a percentage.

Conditional Distribution

This tells you what group you're focusing on.

Frequency

how many people

Independent

conditional percentages are approximately the same.

categorical

Data that places individuals into groups/categories rather than measuring a numerical amount.

Quantitative

Data that represents a numerical amount or measurement that you can do meaningful calculations with.

SOCS (describe the distribution)

S — Describe the overall shape

O — Outliers Mention any unusually high or low scores.

C — Center Give a measure of center, usually the mean or median.

S — Spread Give a measure of spread, usually the standard deviation or IQR.

The distribution of standardized test scores is approximately symmetric with no apparent outliers. The center is around 82 points, and the standard deviation is approximately 7 points.

5 number summary

Min-lowest

Max -highest

Q1- (n+1/4)

Q3-3(n+1/4)

Median-(25+1/2)

how to find outliers

IQR=Q3-Q1

Q1-1.5(IQR)

Q3+1.5(IQR)

Shape

Unimodal=1 hump.

Bimodel= 2 humps

Standard deviation

a statistical measure that shows how far the numbers in a data set are spread out from the average

simpsons paradox

trend appears in several separate groups but reverses or disappears when you combine all the groups together.