The mean wait time at the drive-through of a fast food restaurant from the time
ID: 3351273 • Letter: T
Question
The mean wait time at the drive-through of a fast food restaurant from the time the order is placed to the time the order is received is 86.8 seconds. A manager devises a new drive-through system that he believes will improve (shorten) wait time. As a test, he initiates the new system at his restaurant and measures wait time for 10 randomly selected orders. The wait times, in seconds, are as follows: 107.4 68.7 57.3 75.8 64.4 93.4 84.180.3 72.2 86.4 a) Using the normal probability plot and the boxplot below, are the conditions for testing the hypothesis satisfied? Please explain your answer. Drise-Through Dedori 123 b) Is the new system effective? Conduct a hypothesis test using the classical approach with a 10% level of significance. c) Based on your results of the hypothesis test-the decision you made in part b, what type of error might have occurred? Please explain.Explanation / Answer
a)
yes ,
b)
One-Sample T: C6
Test of = 86.8 vs < 86.8
Variable N Mean StDev SE Mean 90% Upper Bound T P
C6 10 79.00 14.69 4.65 85.43 -1.68 0.064
p-value = 0.064
since p-value < 0.10
we reject the null hypothesis
c) type i error
A Type 1 Error is a false positive -- i.e. you falsely reject the (true) null hypothesis.