AP Stats - Vocab Quiz 2 (1D-E)

Quiz on 08/28 aka Friday!

Median

the midpoint of a distribution of quantitative data—the number such that about half the observations are smaller and about half are larger.

Mean

the average of all the individual data values

Resistant

A statistical measure not affected much by extreme data values.

Range

the distance between the minimum value and the maximum value.

Standard deviation (s)

measures the typical distance of the values in a distribution from the mean. It is calculated by finding an “average” of the squared deviations of the individual data values from the mean, and then taking the square root.

quartiles

divide an ordered data set into four groups having roughly the same number of values

first quartile (Q1)

he median of the data values that are to the left of the median in the ordered list.

Third quartile (Q3)

he median of the data values that are to the right of the median in the ordered list.

Interquartile range (IQR)

the distance between the first and third quartiles of a distribution of quantitative data

The 1.5 x IQR Rule

An observation is called an outlier if it falls more than 1.5 x IQR above the third quartile or more than 1.5 x IQR below the first quartile.

Five-number summary

consists of the minimum, the first quartile (Q1), the median, the third quartile (Q3), and the maximum.

Boxplot

A visual representation of the five-number summary of a distribution of quantitative data. The box spans the quartiles and shows the variability of the middle half of the distribution. The median is marked with a vertical line segment in the box. Lines extend from the ends of the box to the smallest and largest observations that are not outliers. Outliers are marked with a special symbol such as an asterisk (*)

Percentile

the value with p% of observations less than or equal to it.

Standardized value (z-score)

for an individual value in a distribution of quantitative data tells us how many standard deviations from the mean the value falls, and in which direction.

Back-to-back stemplot

a type of stem-and-leaf plot used to compare two groups of quantitative (numerical) data by sharing a single column of stems in the center, with one group’s leaves extending to the left and the other group’s leaves extending to the right