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Watch Corporation of Switzerland claims that its watches on average will neither

ID: 3314547 • Letter: W

Question

Watch Corporation of Switzerland claims that its watches on average will neither gain nor lose time during a week. A sample of 18 watches provided the following gains (+) or losses (–) in seconds per week.

–0.30

–0.27

–0.34

–0.25

+0.31

–0.20

+0.36

+0.24

–0.19

–0.40

–0.49

–0.55

–0.55

–0.67

–0.03

–0.23

–0.54

+0.08

Is it reasonable to conclude that the mean gain or loss in time for the watches is 0? Use the .02 significance level. At a level of .02 significance, we reject H0: = 0 if t <  or t > . (Negative amounts should be indicated by a minus sign. Round your answers to 3 decimal places.)

Watch Corporation of Switzerland claims that its watches on average will neither gain nor lose time during a week. A sample of 18 watches provided the following gains (+) or losses (–) in seconds per week.

Explanation / Answer

The statistical software output for this problem is:

One sample T hypothesis test:
: Mean of variable
H0 : = 0
HA : 0

Hypothesis test results:

Hence,

a - 1) Reject H0: = 0 if t < -2.567 or t > 2.567

a - 2) Test statistic = -3.080

a - 3) Reject; p - Value is between 0.001 and 0.01

Variable Sample Mean Std. Err. DF T-Stat P-value Data -0.22333333 0.072499718 17 -3.0804717 0.0068