Agolfer would like to test the hypothesis that the variance of his golf score equals 10.0. a random sample of 28 rounds of golf had a sample standard deviation of 3.5. what is the number of degrees of freedom for this hypothesisâ test?

It depends on which statistic test we wish to perform, the formula to find a degree of freedom could be different.

for Normal Distribution test, we do not need to find a degree of freedom

for T-test and Chi-Square test, we do n - 1 to find the degree of freedom, where 'n' is the sample size. 

if we have two different sample size, then the degree of freedom is given by (n₁ + n₂) - 2

We are given only one sample size, n = 28, hence the degree of freedom is 28 - 1 = 27

Ithink the answer is last one.