Question

In a sample of 120 students at a university, the grade point average was 3.2 with a standard deviation of 0.9. estimate the grade point average for the entire university, at a 95% confidence interval.

Answer 1

Answer:

Margin of error =

Get the population standard deviation (σ) and sample size (n).

Take the square root of your sample size and divide it into your population standard deviation.

Multiply the result by the z-score consistent with your desired confidence interval according to the following table:A margin of error tells you how many percentage points your results will differ from the real population value. For example, a 95% confidence interval with a 4 percent margin of error means that your statistic will be within 4 percentage points of the real population value 95% of the time.