Sampling Distribution of a Sample Mean

Question 1

What is the formula for standard deviation of a sample mean if N is greater than or equal to 10n?

Answer 1

σ / sqrt(n)

Question 2

How do we find the mean and standard deviation of a sample given proportions?

Answer 2

Mean = p
Standard deviation = σp-^ = sqrt(p(1-p)/n)

n being the size of the srs
p being the size of the proportion

Question 3

The Normality Rules states that a distribution is approximately normal if…?

Answer 3

np is greater than or equal to 10 and n(1-p) is greater than or equal to 10.