The reason we use t procedures instead of z procedures when carrying out a test about a population mean is that (a) z requires that the sample size be large. (b) z requires that you know the population standard deviation s. (c) z requires that the data come from a random sample or randomized experiment. (d) z requires that the population distribution be perfectly Normal. (e) z can only be used for proportions.

The reason we use t procedures instead of z procedures when carrying out a test about a population mean is that " z requires that the population distribution be perfectly Normal"

Step-by-step explanation:

"Z-test is any statistical test for which the distribution of the test statistic under the null hypothesis can be approximated by a normal distribution."

can you rephrase the question ? it is unclear : -)

step-by-step explanation:

step-by-step explanation: