The value of a test statistic

Question

The claim is that the proportion of peas with yellow pods is equal to 0.25 (or 25%). The sample statistics from one experiment include 540 peas with 148 of them having yellow pods. Find the value of the test statistic. The value of the test statistic is____ (round to two decimal places as needed). 

Answer 1

Let p̂ be the sample proportion and let p₀ be the population proportion. Then p̂=148/540 and p₀=.25. Also let n represent the sample size. The formula for the test statistic is as follows:

 

z= (p̂-p₀)/sqrt(p₀(1-p₀)/n) = [(148/540)-.25]/sqrt(.25(1-.25)/540) = 1.29.