Which of the following is not a required condition for performing a z test about an unknown population mean µ?
A. The data represent n independent observations.
B. The population distribution is Normal or the sample size is large (say n>30).
C. The data can be viewed as a simple random sample from the population of interest.
D. The population standard deviation is known.
E. np≥10 and nq≥10.
Answer: E