Practice with Residuals Terms of Use    Contact Person: Donna Roberts
Directions: Read carefully. These questions pertain to residuals.

Questions 1-3 pertain to the chart at the left of residual plots..

1. Which of the residual plots indicates that a linear regression will be appropriate for the data it represents?
Choose:
 A B C

2.
Residual plot B tells you that the regression equation was a quadratic regression and that it is appropriate for the data.
Choose:
 TRUE FALSE

3.
Residual plot C shows the pattern needed to ensure a good linear regression fit.
Choose:
 TRUE FALSE

4.  The linear regression equation shown at the right is y = 4.7x + 51. The scatter plot at x = 5 is (5,90). What is the residual associated with the point where x = 5?

 Choose: 164.5 74.5 15.5 15

5.  A rapidly growing bacteria has been discovered. Its growth rate is shown in the chart at the right.

a) Which choice is the least squares linear regression equation for this data?
(rounded to nearest hundredths with Hours on x-axis, Bacteria on y-axis)
Choose:
 y = 94.17x + 53.43 y = 86.37x + 0.93 y = 94.17x - 53.43 y = 86.37x - 0.93
 Hours since observation began Number of bacteria in the sample 0 20 1 40 2 75 3 150 4 297 5 510

b) Find the residuals associated with this data. Which of the following is the value of the residual associated with the data point (3,150)? (round to nearest hundredths)
Choose:
 73.43 -79.09 -59.91 -26.26

c)
When plotted, the scatter plot of the residuals shows that a linear regression is an appropriate model for this data.
Choose:
 True False

6.  A scatter plot of the residuals from a linear regression are shown at the right. The plots are (1,1.3), (2.-2.2), (3,1.6), (4,-1.1), and (5,0.4). Which statement is true about the sum of the residuals?
Choose:
 The sum is positive. The sum equals zero. The sum is negative. The sum is unknown.

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