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: So Cal Edison
Southern Cal Edison
Southern Cal Gas
Sample Size
9
12
Sample Mean
3.2 min
2.8 min
Sample Standard deviation
0.5 min
0.7 min
Assume the distributions of time a customer is on hold are approximately normal.
Using the following null and alternate hypothesis:H0:mu1-mu2=0 vs. Ha:mu1-mu2 not equal 0Test statistic is t=-1.455Assume alpha = 0.1 what is the appropriate conclusion for this test?
Reject Ha
Reject H0
Do not reject H0
none of these
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