A computer program designer has developed an online questionnaire that she believes will take a mean time of 12 minutes to complete. Suppose that she samples 38 volunteers and find that the mean time...

A computer program designer has developed an online questionnaire that she believes will take a mean time of 12 minutes to complete. Suppose that she samples 38 volunteers and find that the mean time to complete the questionnaire is 11.4 minutes. Determine if there is sufficient evidence to conclude that the mean completion time for the online questionnaire differs from its intended duration. Use a 0.10 level of significance and assume that the population standard deviation is known to be 2.2 minutes.