Question

1) You work for a soft-drink company in the quality control division. You are interested in the standard deviation of one of your production lines as a measure of consistency. The product is intended to have a mean of 12 ounces, and your team would like the standard deviation to be as low as possible. You gather a random sample of 15 containers. Estimate the population standard deviation at a 90% level of confidence.

11.9	12.1	12.09	12.03	11.9
12.06	12.04	11.91	12.07	11.96
11.99	11.94	11.93	11.94	11.91

(Data checksum: 179.77)

Note: Keep as many decimals as possible while making these calculations. If possible, keep all answers exact by storing answers as variables on your calculator or computer.

a) Find the sample standard deviation:

b) Find the lower and upper χ2 critical values at 90% confidence:
Lower:    Upper:

c) Report your confidence interval for σσ: (  ,  )

2) You measure 48 backpacks' weights, and find they have a mean weight of 71 ounces. Assume the population standard deviation is 6.1 ounces. Based on this, construct a 99% confidence interval for the true population mean backpack weight.

Give your answers as decimals, to two places

---------- ± ------ ounces

Answer 1

pls upvote...!!!