Question 867250: An oil change shop advertised to change oil within 15 minutes. Based on the data collected below, what is the probability that an oil change will take 15 minutes or less time? (please share your calculation steps, using the standard normal distribution) Based on this data, do you think the business claim is valid? Explain why or why not.
Oil changes (minutes): 10, 7, 8, 8, 10, 9, 11, 15, 14, 15, 14, 12, 12, 11, 11, 14, 15, 13, 13, 13, 14, 15, 26, 28, 21, 22, 22, 21, 16, 16, 18, 19, 20, 21, 19, 18, 17,16, 16, 16
Answer by ewatrrr(24785)   (Show Source):
You can put this solution on YOUR website!
Hi
Was simply asking You to verify the data
prior to calculations: these give m = 15.4, sd = 4.8
z = (15.4-15)/(4.8/sqrt(40) = .4/.759 = .5270
15min a respectable claim
10 -5.4 29.16
7 -8.4 70.56
8 -7.4 54.76
8 -7.4 54.76
10 -5.4 29.16
9 -6.4 40.96
11 -4.4 19.36
15 -0.4 0.16
14 -1.4 1.96
15 -0.4 0.16
14 -1.4 1.96
12 -3.4 11.56
12 -3.4 11.56
11 -4.4 19.36
11 -4.4 19.36
14 -1.4 1.96
15 -0.4 0.16
13 -2.4 5.76
13 -2.4 5.76
13 -2.4 5.76
14 -1.4 1.96
15 -0.4 0.16
26 10.6 112.36
28 12.6 158.76
21 5.6 31.36
22 6.6 43.56
22 6.6 43.56
21 5.6 31.36
16 0.6 0.36
16 0.6 0.36
18 2.6 6.76
19 3.6 12.96
20 4.6 21.16
21 5.6 31.36
19 3.6 12.96
18 2.6 6.76
17 1.6 2.56
16 0.6 0.36
16 0.6 0.36
16 0.6 0.36
616 903.6 0
15.4 23.17846154
4.814401473 SD
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