You want to estimate today's mean temperature, so you make a series of measurements (taken as a sample) throughout the day. The mean of these measurements is 63 degrees Fahrenheit, and their standard deviation is 3.4 degrees Fahrenheit. For each of the following sampling scenarios, determine which test statistic is appropriate to use when making inference statements about the population mean.
(In the table, refers to a variable having a standard normal distribution, and refers to a variable having a t distribution.)

for the following scenario's please choose one of the following: Z, t, could use either Z or t, unclear:
The sample size has 16, and it is from a population with a distribution about which we know very little.

The sample has size 90, and it is from a non normally distributed population.

The sample has size 75, and it is from a non normally distributed population with a known standard deviation of 4.

The sample has a size 11, and it is from a normally distributed population with unknown standard deviation.

The sample has size 20, and it is from a normally distributed population with known standard deviation of 4.