Test Statistic

The sample size is greater than or equal to 30.

• t-test

• z-test

The population variance is known.

• t-test

• z-test

The population variance is unknown.

• t-test

• z-test

The sample size is below 30.

• t-test

• z-test

The Central Limit Theorem is applied.

• t-test

• z-test

A random sample of the starting salaries of 35 randomly selected graduates with bachelor’s degrees last year gave sample mean and standard deviation P12, 000 and P500 respectively.

• t-test

• z-test

The mean household income in a region served by a chain of clothing stores is P20,000 . In a sample of 20 customers taken at various stores the mean income of the customers was P21,500 with standard deviation P2,852.

• t-test

• z-test

One water quality standard for water that is discharged into a particular type of stream or pond is that the average daily water temperature be at most 18⁰ F . A sample of 10 gave a mean temperature of 18.7˚F.

• t-test

• z-test

The average height of grade 11 learners is 160cm. 40 randomly selected learners have a mean height of 157cm with a standard deviation of 3cm.

• t-test

• z-test

The head teacher of Mathematics department of a certain school claims that the average grade of Grade 11 learners in Statistics and Probability is 85. Test the claim if 15 randomly selected samples have a mean grade of 83 with a standard deviation of 3.

• t-test

• z-test