A customer service representative was interested in comparing the average time (in minutes) customers are placed on hold when calling Southern California Edison and Southern California Gas companies. The representative obtained two independent random samples and calculated the following summary information:
Edison: n1= 9 xbar1= 3.2 s1= 0.5min
Gas: n2= 12 xbar2= 2.8 s2= 0.7min
Assume the distributions of time a customer is on hold are approximately normal.
In a minimum of 5 steps, show work: Perform an appropriate hypothesis test to test whether there is a significant difference in average time a customer is on hold between the two companies. Use the .10 significance level.