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In: Statistics and Probability

6. A researcher is interested in whether increasing the tire pressure of an automobile will lead...

6. A researcher is interested in whether increasing the tire pressure of an automobile will lead to better gas mileage. He collects a sample of automobile owners and measures the MPG. After increasing the tire pressure, he measures the MPG a second time. The data for both measurements is listed below. Was gas mileage significantly higher after increasing the pressures? [note: you will need to calculate the sum of difference scores in order to find the mean of the differences] (5 points total, show all steps)

Car

X1 (original pressure)

X2 (final pressure)

A

14

15

B

21

23

C

30

33

D

17

19

E

19

21

F

25

27

n=6

M1 = 21,

M2 = 23,

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Ans.

Obs. X1 X2 d=X1-X2 d2
1 14 15 -1 1
2 21 23 -2 4
3 30 33 -3 9
4 17 19 -2 4
5 19 21 -2 4
6 25 27 -2 4
SUM = -12 26

orchestra answered 2 years ago
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