The data entry operator in a large computer department claims that it gives its customers a completion time of 6.0 hours or less. To test this claim, one of the customers took a sample of 26 jobs and found that the sample mean completion time was 6.5 hours with a sample standard deviation of 1.5 hours. Use 5% level of significance to test the data entry operation's claim. Assume that the completion times have an approximately normal distribution.