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## Hypothesis Test for a Mean: Pop. Stdev. Unknown

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**Hypothesis Test for a Mean: Pop. Stdev. Unknown**The average work week for employees in an internet start up company is believed to be about 65 hours. A newly hired marketing employee hopes that it is shorter so he surveys 12 employees in the company for the lengths of their average work week and conducts a hypothesis test. Data: 70, 50, 45, 55, 65, 67, 68, 68, 48, 49, 66, 54 Ho: µ = 65 Ha: µ < 65**Hypothesis Test for a Mean: Pop. Stdev. Known**= the average length of an average work week for the internet start-up company. Distribution for the Test: Student-t: t11 degrees of freedom = df = 12 – 1 = 11**Hypothesis Test for a Mean: Pop. Stdev. Known**USE A TTEST. Test statistic: t = -2.31 Standardized score, t-score, for which is calculated from the data. p-value: 0.0208**Hypothesis Test for a Mean: Pop. Stdev. Known**Decision: Assume REJECT Ho. Conclusion: There is sufficient evidence to conclude that the length of an average work week is shorter than 65 hours, on the average.