Critical Numbers 5: Estimation Inference

Question 1

what is the central limit theorm?

Answer 1

If we were to take repeat samples and calculate the mean each time those sample means will be Normally distributed around the true population mean even if the population itself is not Normally distributed

Question 2

what is the standard error? what does it show?

Answer 2

Measures howdiffernet a sample’s mean is likely to be compared with the population mean.
It is the standard deviation of the sampling distribution

precision of estimation

Question 3

Standard error formula? what two things affect it

Answer 3

Standard error of the mean = SD/√n

variability of data- SD, smaple size- n

Question 4

What are confidence intervals?
whats formula for calculating if it falls within or not?

Answer 4

This is the range of values you expect your estimate to fall between if you redo your test, within a certain level of confidence.

mean +or- 1.96 times Standard Error

Question 5

point estimate vs interval estimate

Answer 5

-best estimation of population mean
-range we think population mean falls within to 95% confidence

Question 6

clinical significance vs statistical significance

Answer 6

Statistical significance just means an observed result is unlikely under the null hypothesis

Clinical importance means the result is practically important/meaningful in the real world

Just because a result is statistically significant doesn’t mean it is clinically important!

Question 7

Standard error vs standard deviation

Answer 7

If we want to describe the dispersion around the mean in our sample data we use the standard deviation

If we want to quantify the precision of a sample estimate of a population parameter such as the mean value we use the standard error

Question 8

what is used when claculating reference range vs confidence level?

Answer 8

When calculating a reference range use the standard deviation
When calculating a confidence interval use the standard error