B) A random sample of 16 mid-sized cars tested for fuel consumption gave a mean of 26.4Kilometers per liter with a standard deviation of 2.3 kilometers per liter.

i) Assuming that the kilometers per liter given by all mid-sized cars have a normal distribution, find a 99% confidence interval for the population mean μ

1 answer

99% = mean ± Z (SEm)

SEm = SD/√n

Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability (.005) in the smaller area and its Z score. Insert data into equations above.