Question

consider the following results frmo two independent random samples taken from two populations. assume that the variances are NOT equal.

	Population 1	population 2
sample size	50	50
sample mean	35	30
sample variance	784	100

a) what is the "degrees of freedom" for these data?

b) what is the 95% confidence interval difference of the population means?

Answer 1

a) what is the "degrees of freedom" for these data?

Degree of freedom formula is n-1

N = sample size

Here in both population 1 and 2 sample size would be 1

so n=1

DF = 1-1 = 0

b) what is the 95% confidence interval difference of the population means?

square root of variance is called as standard deviation

95 % confidence interval for population 1 (27.24, 42.76)

95 % confidence interval for population 1 (26.36, 33.64)

sample variance = 784

SD = Sqrt(784) = 28

sample variance = 100

SD = sqrt(100) = 10