Out of 57 subjects, there are 43 successes. This means that the probability of success, p' would be
p' = 43/57 = 0.75
Thus, Sample proportion = 0.75
The claimed proportion, p = 0.72
Test statistic = (Sample proportion - claimed proportion)/standard error
The formula for calculating standard error is expressed as
[tex]\begin{gathered} \text{standard error = }\sqrt[]{\frac{pq}{n}} \\ p\text{ = 0.72} \\ q\text{ = 1 - 0.72 = 0.28} \\ n\text{ = 57} \\ \text{Standard error = }\sqrt[]{\frac{0.72\times0.28}{57}}=0.05947 \end{gathered}[/tex]
Claimed proprortion = 0.72
Test statistic = (0.75 - 0.72)/0.05947
z = 0.50
