Problem
The owner of Birmingham Cycles is considering a new method of assembling its cycles. At present, the mean time for assembling a cycle is 29 minutes. Birmingham used the new method recently on a sample of 20 cycles where the mean time was 27 minutes and standard deviation was 1.8 minutes.
Using the .10 level of significance, can we conclude that the assembly time using the new method is faster?
Will your answer change if you use a .05 level of significance?