1. The meanreplacement time for a random sampleof 12 microwave ovens is 8.6 years with a standard deviationof 4.2 years. Construct a 98% confidence intervalfor the population varianceo^2. Assume the dataare normally distributed.
A. (7.8,63.6) B. (1.9,15.1) C. (2.8,8.0) d. (7.4,54.3)
2. The dean of a major university claims that the mean time for students to earn a Master’s degree is at most 3.8 years. It a hypothesis testis performed, how should you interpret a decision that fails to reject the null hypothesis?
A. There is not sufficient evidence to reject the claim that the mean is less than or equal to 3.8
B. there is sufficient evidence to reject the claim that the mean is less than or equal to 3.8.
C. There is not sufficient evidence to support the claim that the mean is less than or equal to 3.8.
d. there is sufficient evidence to support the claim the mean is less than or equal to 3.8.
The solution provides step by step method for the calculation of confidence interval for population variance. Formula for the calculation and Interpretations of the results are also included. Interactive excel sheet is included. The user can edit the inputs and obtain the complete results for a new set of data.