AP Stats Chapter 3

If bivariate data set A has correlation r = 0.95, and a second bivariate data set B has correlation r = –0.95, then

• a linear model does a better job of describing the relationship between the variables in data set A than in data set B.

• a linear model does a better job of describing the relationship between the variables in data set B than in data set A.

• a linear model is the best description of the relationship between the variables in both data set A and data set B.

• you can’t tell whether either data set is best described by a linear model until you examine the scatterplots.

• a mistake has been made—r cannot be negative.

A copy machine dealer has data on the number of copy machines x at each of 89 customer locations and the number of service calls in a month y at each location. Summary calculations give x̅= 8.4, sx= 2.1, y̅= 14.2, sy= 3.8, and r = 0.86. What is the slope of the least-squares regression line of number of service calls on number of copiers?

• 0.86

• 1.56

• 0.48

• 2.82

• cannot tell from the information given

Suppose we fit a least-squares regression line to a set of data. What is true if a plot of the residuals shows a curved pattern?

• a straight line is not a good model for the data

• the correlation must be 0

• the correlation must be positive

• outliers must be present

• The regression line might or might not be a good model for the data, depending on the extent of the curve.

This table displays counts and percentages of individuals falling into named categories on two or more variables

• Frequency table

• Relative Frequency table

• Contingency table

• Data table

In a contingency table, the distribution of one variable for just the cases that satisfy another variable (either by row or by column)

• Marginal distribution

• Conditional distribution

• Independent distribution

• Frequency distribution

A display with bars used for quantitative data that shows frequency for each bin

• Histogram

• Bar Chart

• Pie Chart

• Segmented Bar Chart

A distribution where each side is a mirror image of the other and is roughly bell-shaped

• Uniform

• Skewed

• Asymmetric

• Symmetric

The parts of a skewed distribution that trail off either on the left or right side

• Ends

• Tails

• Gaps

• Mode

Extreme values that don't appear to belong with the rest of the data

• Maximum

• Outliers

• Minimum

• Mode

If the distribution is symmetric, we report

• Mean and Standard Deviation

• Median and Standard Deviation

• Median and IQR

• Mean and IQR