# AP Stats Chapter 1

## 20 terms · Vocabulary specifically from the Practice of Statistics, an AP Statistics course.

### Individuals

the objects described by a set of data. They may be people, animals or things.

### Variable

Any characteristic of an individual that can take different values for different individuals.

### Categorical Variable

This places individuals into certain groups or categories.

### Quantitative Variable

This takes a numerical value for which arithmetic operations such as adding and averaging make sense.

### Distribution

This of a variable tells us what values the variable takes and how often it takes these values.

### Outlier

An individual observation that falls outside the overall pattern of the graph.

### Symmetric

If a histrogram of a certain distribution has both the right and left sides approximately equal.

### Skewed Right

A distribution in which the right side of the histrogram (containing the half of observations with larger values) extends much farther out than the left.

### Skewed Left

A distribution in which the left side of the histrogram (containing the half of observations with larger values) extends much farther out than the right.

### Percentile

the "nth" of this of a distribution is the value such that n percent of the observations fall at or below it.

### Median

The midpoint of a distrbiution, the number such that half the observations are smaller and the other half are larger.

### Mean

The average of all the data.

### First Quartile

The median of the observations whose position in the ordered list is to the left of the location of the overall median.

### Third Quartile

The median of the observations whose position in the ordered list is to the right of the location of the overall median.

### Interquartile Range

The distance between the first and third quartiles.

### Five-Number Summary

This of a data set consists of the smallest observation, the first quartile, the median, the third quartile, and the largest observation, writting in order from smallest to largest.

### 1.5 X IQR

Call an observation an outlier if it falls more than ___________ above the third quartile.

### Modified Boxplot

This is a graph of the five-number summary, with outliers plotted individually.

### Variences s²

This of a set of observations is the average of the square of the deviations of the observations from their mean.

### Standard Deviation s

is the quare root of the variance s².