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Question 1 A study is conducted to compare the effect of stress in the form of noise on the ability to perform a simple task by 50 subjects. The first group of 25 subjects acted as a control, while the second group of 25 was the experimental group. Both group subjects had to perform the task but only the experimental group subjects had to perform the task with loud music played on. The time to finish to finish the task was recorded for each subject and the following summary was obtained: Control 25 Experimental 25 15 minutes 4 minutes Number of samples Sample mean 23 minutes Sample standard deviation 10 minutes Assume that the time to finish the task follows a normal distribution for both populations. Test at a = 0.05 whether the mean time to finish the task for the experimental group is higher than the control group. Assume that there is a difference between the two population variances. (7 marks)