Answer: a. 4
Explanation:
The number of degrees of freedom represents the number of data-values in the evaluation of a test-statistic that are independent to vary.
The degree of freedom for chi-square test = n-1 , n= Sample size.
Given : A study was conducted to examine whether the proportion of females was the same for five groups (Groups A, B, C, D, and E).
i.e. n= 5
Then, the number of degrees of freedom the χ2 test statistic have when testing the hypothesis that the proportions in each group are all equal = 5-1=4
Hence, the correct answer is OPTION a. 4 .