Question

In an August 2012 Gallup survey of 1,012 randomly selected U.S. adults (age 18 and over), 536 said that they were dissatisfied with the quality of education students receive in kindergarten through grade 12.

a. Test, at the 5% significance level, if this sample provides evidence that the proportion of Americans who are dissatisfied with education in kindergarten through grade 12 differs significantly from 50%.
b. Is the Test Significant? Why or Why not.

Answer 1

Yes, result is significant ; PVALUE < α

Explanation:

Given :

x = 536

n = sample size = 1012

Phat = x / n = 536 / 1012 = 0.5296 = 0.53

H0 : P0 = 0.5

H1 : P0 > 0.5

Test statistic :

(Phat - P0) ÷ sqrt[(P0(1 - P0)) / n]

1-P0 = 1 - 0.5 = 0.5

(0.53 - 0.5) ÷ sqrt[(0.5*0.5)/1012]

0.03 ÷ 0.0157173

= 1.9087

Pvalue :

Using the Pvalue from test statistic :

Pvalue = 0.02815

To test if result is significant :

α = 0.05

0.02815 < 0.05

Pvalue < α ; Hence, result is significant at α=0.05; Hence, we reject H0.