Posted by Janice on Wednesday, February 10, 2010 at 5:54pm.
A recent article in a computer magazine suggested that the mean time to fully learn a new software program is 40 hours. A sample of 100 firsttime users of a new statistics program revealed the mean time to learn it was 39 hours with the standard deviation of 8 hours. At the 0.05 significance level, can we conclude that users learn the package in less than a mean of 40 hours?

Statistics  MathGuru, Monday, February 22, 2010 at 8:32pm
Ho: µ = 40 >population mean = 40
Ha: µ < 40 >population mean < 40
Using a onesample ztest:
z = (sample mean  population mean)/(standard deviation divided by the square root of the sample size)
With your data:
z = (39  40)/(8/√100)
Finish the calculation. Determine whether or not to reject the null using 0.05 level of significance for a onetailed test.
I hope this will help.