Sampling and Estimation

Question 1

Calculate sampling error of the mean

Answer 1

sample mean – population mean = x − μ

Question 2

Standard Error of the Sample Mean (Known Population Variance)

Answer 2

Standard Deviation / Square root of N samples

Question 3

Standard Error of the Sample Mean (Unknown Population Variance)

Answer 3

Standard deviation in unknown population’s sample / Square root of N samples

Question 4

Confidence intervals: When do you use a z-statistic?

Answer 4

When the variance is known, normal non normal, large or small sample size

Question 5

Confidence intervals: When do you use a t-statistic?

Answer 5

Unknown variamce, normal non normal, large or small sample size

Question 6

What is a large / small sample size

Answer 6

Small < 29
Large 30 +

Question 7

How do you compute a confidence interval using standard deviation?

Answer 7

1. mean
   2 +-
   3 No. confidence interval
2. SD

Question 8

How do you compute a confidence interval using standard error?

Answer 8

1. mean
2. +-
3. confidence interval
4. SE