Estimation of Population in parameters in z-distribution

4. Every employee of Space Electronix took a weight test. The average weight of 240 employees are 70 kg and the standard deviation of sample is 29 kg. Find the interval estimate of population mean in 95% confidence level.

5.Duke Colleges wants to know the time in class they will execute on the upcoming school year. On average, 65 classroom has 8 hours of class and the standard deviation sample is 3 hours. Find the interval estimate of population in 90%