AP Statistics Scatterplots and Correlation Quiz: 10 Questions with Explanations

A About 0.9B About 0C About -0.9D About 1.5

There is no linear pattern, so r is near 0. r can never be 1.5 because |r| <= 1.

A a strong negative linear associationB a strong positive linear associationC a curved associationD no association

The points fall in a nearly straight pattern, so the direction is negative and the strength is high.

A -0.4B 0C -1D 1.3

r must lie between -1 and 1 inclusive.

A 0.6B 6C 0.06D 60

A linear change of units does not change r.

A It raises rB It does not affect rC It makes r negativeD It lowers r compared with the other points

The point lies far from the otherwise linear pattern and increases the scatter, so r decreases.

A that x causes yB that y causes xC an association, not necessarily causationD that the relation is curved

Correlation does not prove causation; lurking variables could be responsible.

A Height and arm lengthB Hours of TV per week and test scoresC Age of child and shoe sizeD Temperature and ice cream sales

More hours of TV go with lower scores in many studies. The other pairs usually rise together.

A strongerB weakerC the same strengthD impossible

Strength depends on |r|, and 0.8 is greater than 0.6.

A 1B -1C 0D 0.5

Positive and negative parts cancel, so the linear correlation is near 0 although the relationship is strong.

A horizontal axisB vertical axisC either axisD a third axis

The explanatory variable is on the x-axis, and the response variable goes on the y-axis.