Statistics
posted by Amy on .
A study in Orlando, Florida claimed that the mean commute time for all employees working at Disney exceeds 40 minutes. This figure is higher than what was assumed in the past. The plan is to test this claim at a level of significance = 0.05 and a sample size = 100 commuters. For this sample size, it was found the sample mean is 43.5 minutes. Based on previous studies, assume the standard deviation is known to be o = 8 minutes. Conduct a hypothesis test using a rejection region and draw a conclusion.

Try a onesample ztest.
Hypotheses:
Ho: µ = 40 >null hypothesis
Ha: µ > 40 >alternate hypothesis
z = (sample mean  population mean)/(standard deviation divided by the square root of the sample size)
With your data:
z = (43.5  40)/(8/√100) = ?
Finish the calculation.
Check a ztable at level 0.05 for a onetailed test.
If the ztest statistic exceeds that value from the ztable, reject the null and conclude µ > 40. If the ztest statistic does not exceed the that value from the ztable, do not reject the null (you cannot conclude a difference).
I hope this will help get you started.