To compare the effect of stress caused by noise on the ability to perform a simple task, 84 subjects were divided into two groups-37 subjects as a control group, and 47 subjects as the experimental...

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The confidence interval in part (a) has

---Select--- one positive and one negative endpoint, two negative endpoints, or two positive endpoints. Hence, it is

---Select--- not likely or plausible
that the means are equal. Based on the data we would conclude that
---Select--- there is no evidence of or there is

 a real difference in the mean times to completion for the two groups.

Extracted text: To compare the effect of stress caused by noise on the ability to perform a simple task, 84 subjects were divided into two groups-37 subjects as a control group, and 47 subjects as the experimental group. Although each subject performed the task, the experimental group had to perform the task while loud rock music was played. The time to finish the task was recorded for each subject and the following summary was obtained. Control Experimental in 37 47 17 minutes 26 minutes 5 minutes 11 minutes (a) Find a 99% confidence interval for the difference in mean completion times (in minutes) for these two groups. (Calculate the difference as the control group - the experimental group. Round your answers to two decimal places.) min to min (b) Based on the confidence interval in part (a), is there sufficient evidence to indicate a difference in the average time to completion for the two groups? Explain. The confidence interval in part (a) has ---Select--- |. Hence, it is ---Select--- v that the means are equal. Based on the data we would conclude that ---Select--- va real difference in the mean times to completion for the two groups.