POWERPOINT 3

Question 1

sample counterpart of the mean; unbiased and consistent

Answer 1

sample mean (Xbar)
                n
Xbar = 1/n

Question 2

sample counterpart of the variance

Answer 2

sample variance (s^2)
              n
s^2 = 1/n

Question 3

expected value of the sample mean

E(Xbar) = μ

Answer 3

true mean

Question 4

variance of sample mean

Answer 4

Var (Xbar) = σ^2/n

Question 5

sampling distribution of the mean; lets us evaluate the uncertainty associated with our estimate of the mean

Answer 5

Xbar~N(μ, s^2/n)

Question 6

sXbar = sqrt(s^2/n)

Answer 6

standard error of Xbar

Question 7

[Xbar ±2 × sX ̄ ] gives a 95% range of plausible values for μ

Answer 7

95% confidence interval for μ

Question 8

sphat = sqrt(phat(1-p)/n)

Answer 8

standard error associated with the sample proportion as an estimate of the true proportion

Question 9

phat ±2 x sphat

Answer 9

95% confidence interval for proportion (p)