Stats Unit 2 Vocabulary

Relative Risk

Ratio of proportions between two Explanatory Variables

Simpson’s Paradox

Proportions reverse direction

Outlier

An observation that falls outside the overall pattern of the graph

Symmetrical Distribution

The right and left side of a histogram are approximately mirror images of each other

Right Skewed Distribution

The RIGHT side of the histogram extends father out than the left side. RIGHT tail

Left Skewed Distribution

The LEFT side of the histogram extends father out than the right side. LEFT tail

Describing a Distribution

Shape, Center, Spread, Outliers

Median

Middle value of the distribution

Resistant

Does not change when data values change

Mean X(bar)

Average

Range

Max – Min

Lower Quartile Q1

25% of the data values are below this value

Upper Quartile Q3

75% of the data values are below this value

Interquartile Range

IQR (Q3-Q1)

Five Number Summary

Minimum, Q1, Median, Q3, Maximum; used to describe a skewed distribution

Standard Deviation  S

Average distance a data value is from the mean

Mean & Standard Deviation

Used to describe a symmetrical distribution

Empirical Rule

68%-95%-99.7%

Standardize z-score

Z-score=(OBS-Mean)/Standard deviation