Quiz about AP Stat Scatter Plots

Question 1

Describe the relationship between the variables.

Accepted Answer

no correlation

Answer

strong positive correlation

Answer

strong negative correlation

Answer

weak positive correlation

Question 2

Describe the correlation in the graph shown.

Accepted Answer

Strong Positive

Answer

Strong Negative

Answer

Weak Negative

Answer

Weak Positive

Question 3

Describe the correlation in the graph shown.

Accepted Answer

No Correlation

Answer

Strong Negative

Answer

Strong Positive

Answer

Weak Negative

Question 4

Describe the correlation in the graph shown.

Accepted Answer

Strong Negative

Answer

Strong Positive

Answer

Weak Negative

Answer

Weak Positive

Question 5

Estimate the correlation coefficient.

Accepted Answer

r=0

Answer

r=-1

Answer

r=1

Answer

r=2

Question 6

The scatter plot shows the relationship between the number of chapters and the total number of pages for several books. Use the trend line to predict how many chapters would be in a book with 180 pages.

Accepted Answer

18 chapters

Answer

12 chapters

Answer

15 chapters

Answer

21 chapters

Question 7

If Joe worked 30 hours, how much is he expected to earn?

Accepted Answer

$600

Answer

$200

Answer

$1000

Answer

$800

Question 8

If Gold's Gym is looking to buy 30 TVs, how much will each one cost?

Accepted Answer

400

Answer

750

Answer

1250

Answer

0

Question 9

The chart below tracts starting salaries for health care workers since the year 2000. Find the least squares regression equation.

Accepted Answer

yhat = 27541.812 + 839.721x

Answer

yhat = -839.721 + 27541.812x

Answer

yhat = 839.721 + 27541.812x

Answer

yhat = -27541.812 + 839.721x

Question 10

Some data were collected on the weight of a male white laboratory rat for the first 25 weeks after its birth. The linear regression equation is:

Weight = 100 + 40(Time).

Which is the best description of the slope for this regression equation in context of the problem?

Accepted Answer

The slope is 40 grams/week which means the mouse gains about 40 grams per week after birth.

Answer

The slope of the line of regression is the time since birth of the rat. It demonstrates the predicted weight of a laboratory rate after so many weeks since birth.

Answer

The slope is 40 and it means for every increase in weeks the graph will increase.

Answer

The slope is 40, which tells us the line increases.

Question 11

Which is the best description of the y - intercept for the linear regression equation of the rats: Weight = 100 + 40(Time)?

Accepted Answer

The y-intercept is 100, which means the rat is predicted to weigh 100 grams at birth.

Answer

The y-intercept is 100, which is where the graph crosses the y-axis.

Answer

100 is where the data starts on the y-axis.

Answer

The y-intercept is 100, which means at a weight of 0, the rat will take 100 seconds.

Question 12

How do you calculate a residual?

Accepted Answer

Observed - Predicted

Answer

Predicted - Observed

Question 13

Interpret the slope of the Least Squares Line Equation.

Accepted Answer

As hours increases by one, income will increase by 31.45.

Answer

Income increases by 31.45 with each additional 2 hours worked.

Answer

Income increases by 31.45

Answer

As hours increases by one, income will decrease by 242.3.

Question 14

The coefficient of determination of the linear relationship between Florida boat registrations and manatee deaths was found to be r² = 0.897. Which of the following is the correct interpretation of the r²?

Accepted Answer

89.7% of the variability in manatee deaths is explained by the least squares regression line of manatee deaths on Florida boat registrations.

Answer

89.7% of manatee deaths are due to the number of Florida boat registrations.

Answer

0.947 is the correlation between Florida boat registrations and manatee deaths.

Answer

Correlation is not causation so we cannot make any interpretations ever.

Question 15

Which of the following residual plots indicates that a linear relationship exists between the two variables?

Accepted Answer

Option A is correct

Answer

B.

Answer

C.

Answer

D.

Question 16

Which of the following is true of the correlation r?

Accepted Answer

It's between -1 and 1 inclusively.

Answer

It is a resistant measure of association

Answer

If r is the correlation between X and Y, then -r is the correlation between Y and X

Answer

Whenever all the data lie on a perfectly straight-line, the correlation will always be equal to +1.0

Question 17

A least-squares regression line for predicting performance on a college entrance exam based on high school grade point average (GPA) is determined to be
predicted score = 273.5 + 91.2(GPA)
One student in the study had a high school GPA of 3.2 and an exam score of 550. What is the residual for this student?

Accepted Answer

-15.34

Answer

15.34

Answer

40.23

Answer

-40.23

Question 18

Making the statement:
There is a positive linear correlation.
is an example of what?

Accepted Answer

Interpreting r

Answer

Interpreting r²

Answer

Interpreting a Residual Plot

Answer

Interpreting Standard Deviation

Question 19

Shown is a residual plot. Would a linear regression model of the data be most appropriate?

Accepted Answer

YES

Answer

NO

Question 20

A sociologist studying the relationship between early childhood nutrition and academic achievement in middle school among children in a certain city finds that the correlation between these two variables is 0.86. Which of the following conclusions can he draw from this study?

Accepted Answer

Children in this city who have a healthy diet in early childhood tend to do better in middle school.

Answer

Ensuring good nutrition in early childhood will increase academic achievement for middle school students.

Answer

Since the correlation is so low, no conclusions can be drawn.

Question 21

Based on the residual plot would you say the regression line is a pretty good fit?

Accepted Answer

No

Answer

Yes

Answer

Maybe

Answer

Need more info

Question 22

The scatter plot shows the number coffee shops in different cities and the number of violent crimes. Which of the following is NOT true?

Accepted Answer

D) An increase in coffee shops causes an increase in violent crimes

Answer

A) As the number of coffee shops increase, violent crimes appears to increase.

Answer

B) The line of best fit (regression line) shows a positive correlation

Answer

C) The data has a positive correlation coefficient

Question 23

Rank these scatter plots according to the intensity of the correlation represented, from weakest to strongest.

Accepted Answer

1, 3, 4, 2

Answer

1, 2, 3, 4

Answer

2, 4, 3, 1

Answer

4, 3, 2, 1

Question 24

What is the typical prediction error?

Accepted Answer

Answer

Answer

Answer

Question 25

What percent of the variation in Math can be explained by the linear relationship between Math and Verbal?

Accepted Answer

Answer

Answer

Answer

Question 26

A student with a 200 Verbal and 360 Math was added to the sample used to calculate the LSRL. How would this effect the correlation coefficient.

Accepted Answer

The added point is an influential observation and would increase r.

Answer

The added point fits the model and would have little effect on r.

Answer

The added point does not fit the model and would reduce r.

Answer

The added point is an influential observation, but since it fits the model, it would have little effect on r.

Question 27

The _________________ ____________________ measures the strength of the relationship between 2 variables.

Accepted Answer

Correlation Coeffiecient

Answer

Causation

Answer

Independent Variable

Answer

Standard Deviation of the Residuals

Question 28

If you graphed height as the explanatory variable and weight as the response variable, what would happen to the LSRL and r if you had accidently graphed the weight as the explanatory variable and the height as the response variable?