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a) A random sample of 50 recent college graduates result in a mean time to graduate of 4.58 years, with a standard deviation of 1.10 years. Compute and interpret a 90% confidence interval for time to graduate with a bachelor's degree. (10 marks) b) A student used a Secchi disk to measure the clarity of the lake's water by lowering the disk into the water and measuring the distance below the water surface at which the disk is no longer visible. Table 2 shows measurements that were taken on the lake at various points in time over the course of a year. 82 64 62 66 68 43 38 26 68 56 54 66 a) Construct a 95% confidence interval for the mean Secchi disk measurement. Interpret the result. (10 marks) b) Construct a 99% confidence interval for the mean Secchi disk measurement. Interpret the result. (10 marks)