Question

Test the claim that the population of sophomore college students has a mean grade point average greater than 2.25. Sample statistics include n=180, xtopbar =2.43, and s=0.8. Use a significance level of α=0.05.

The test statistic is=

The critical value is=

The P-Value is=

Answer 1

Solution :

This is the right tailed test .

The null and alternative hypothesis is ,

H₀ :   = 2.25

H_a : > 2.25

Test statistic = z

= ( - ) / s / n

= (2.43 - 2.25) / 0.8 / 180

= 3.02

= 0.05

Z _0.05 = 1.645

Critical value = 1.645

P(z > 3.02) = 1 - P(z < 3.02)

P-value = 0.0013