Choose the correct answer:

We use the t distribution to perform a hypothesis test about the population mean when:

a. The population from which the sample is drawn is approximately normal and the population standard deviation is known

b. The population from which the sample is drawn is not approximately normal and the population standard deviation is known.

c. The population from which the sample is drawn is approximately normal or sample size is 30 or larger and the population standard deviation is unknown.

d. The population from which the sample is drawn is not approximately normal and the population standard deviation is unknown.

We use the t distribution to perform a hypothesis test about the population mean when:

a. The population from which the sample is drawn is approximately normal and the population standard deviation is known

b. The population from which the sample is drawn is not approximately normal and the population standard deviation is known.

c. The population from which the sample is drawn is approximately normal or sample size is 30 or larger and the population standard deviation is unknown.

d. The population from which the sample is drawn is not approximately normal and the population standard deviation is unknown.