For Exercises 23–28, we are taking a random sample from a population with unknown. However, do not assume that the population is normally distributed.
27. Confidence level 95%, , ,
8.2.27
(a) (b) We are not told that the population is normal. However, the sample size is large ( is ). (c) (−21, −19). We are 95% confident that the population mean lies between −21 and −19.
(d)