Quiz 11

Questions 21-24 refer to the following situation:

On  his morning commute, a researcher notices that the shorter the interval  of time between traffic light changes, the more vehicles run the red  light. Interested in this relationship, the researcher conducts an  experiment over the next few weeks.  Each morning he first chooses a  traffic light at random. Once the light changes, he begins counting the  number of vehicles running red lights. He continues to count until the  light changes again. The data on six lights is as follows:

Length of Light (X)    Number of Cars (Y)
10                           20
13                            19
19                            17
25                            11
28                            9
30                            8

21. Calculate the regression line.

22. What is the Y-intercept?

23. Calculate the coefficient of determination.

24. “If the length of a light was 7 seconds, how many cars would you predict would run the red light?”

Use the following scenario for 25 only.

Use  the method of regression analysis to test the relationship between  temperature (X) and the number of cars recorded as speeding (Y). Set α =  .05

Temperature    Number of Cars Speeding
50                   10
65   12
80   16
85   16
90   13
70   10
75   12
25. Use  the method of regression analysis to test the relationship between  temperature (X) and the number of cars reordered as speeding (Y). Set  __=.05

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