Question

Nationally, the average GRE score is 500 ( = 500) with a standard deviation of 100 (σ = 100). A group of AAMU students founded a test prep company and developed a curriculum to improve test scores. The company piloted its program on 100 students who earned an average GRE score of 525 (M = 525). Does the new curriculum have any impact on GRE scores? Use the α = .01 significance level.

Answer 1

Sample size = n = 100

Sample mean = = 525

Population standard deviation = = 100

The null and alternative hypothesis is

Level of significance = 0.01

Here population standard deviation is known so we have to use z-test statistic.

Test statistic is

Critical value = 2.32   ( Using z table)

Critical value < Test statistic | z | we reject the null hypothesis.

Conclusion: Yes,  the new curriculum has any impact on GRE scores.