Unit 1 Exploring One Variable Data

AP Statistics Unit 1 Vocabulary Flashcards

Statistic

Any summary information learned from sample data.

Parameter

Any summary information learned from population data.

Variable

Any characteristic that can change from one individual to another.

Categorical Variable

A variable that takes on values that are category names or group labels (e.g., eye color, hair color).

Quantitative Variable

A variable that takes on numerical values that are either measured or counted (e.g., weight, number of candies).

Frequency Table

A table that lists each category and counts how many individuals fall into each category.

Relative Frequency

The proportion of individuals that fall into each category.

Distribution

What values the data takes on and how often it takes on those values.

Discrete Quantitative Variable

Takes on values that are countable and finite (typically whole numbers).

Continuous Quantitative Variable

Takes on values that are not countable and could theoretically be infinite.

Histogram

A graph for quantitative data showing bins/intervals on the x-axis and the frequency/proportion on the y-axis.

Shape

Unimodal, bimodal, gap, clusters, symmetric, skewed left, skewed right.

Center

A value that best summarizes all the data (e.g., mean, median).

Spread

Analysis of how the data varies.

Outliers

Data values that are very far away from all the other values.

Mean

The average value, found by adding all values and dividing by the number of values; easily influenced by outliers.

Median

The middle value when data is ordered; not influenced by outliers.

Percentile

The percentage of data at or below a certain value.

First Quartile (Q1)

The 25th percentile, the middle of the bottom half of the data.

Third Quartile (Q3)

The 75th percentile, having 75% of data below it.

Range

The maximum value minus the minimum value; very easily influenced by outliers.

Interquartile Range (IQR)

The range of the middle 50% of the data, from Q3 to Q1.

Standard Deviation

Represents how far the majority of the data is from the mean.

Fence Method

A method using quartiles to determine outliers.

Five-Number Summary

The minimum, Q1, median, Q3, and maximum values.

Box Plot

A graphical representation of the five-number summary.

Density Curve

Used to model a set of data to give insight into the population.

Normal Distribution

Unimodal, mound-shaped, and symmetric density curve.

Empirical Rule

68% of data is within one standard deviation, 95% within two, and 99.7% within three standard deviations of the mean.

Z-score

Measures how many standard deviations above or below the mean a value is.