Stats 4: Precision and CI

Question 1

Briefly describe the Central Limit Theorem

Answer 1

Repeatedly resample from large sample, would mean sample means would be normally distributed around true population mean

Question 2

What is sample mean?

Answer 2

Best guess of population mean

Question 3

Features of Sample Mean?

Answer 3

1) Close to true population mean,
2) less spread out,
3) normally distributed
4) Likely an over/under estimate

Question 4

Term for sample individuals being similar?

Answer 4

Homogenous

Question 5

What does SE measure and what does a value mean?

Answer 5

1) Measure of precision

2) Smaller SE means estimate is more precise

Question 6

Why does a larger SD result in a larger SE?

Answer 6

More variability means that there is a greater uncertainty

Question 7

How is SE calculated?

Answer 7

SE= SD/√n (N is # people in sample)

Question 8

What is a confidence interval?

Answer 8

Range of values that true value lies in (95%)

Question 9

What are the 2 assumptions of SE?

Answer 9

1) Data is approximately normally distributed

2) Sufficient sample size (at least 20)