Week 6 - Sampling Distributions and Confidence Intervals

Question 1

What does inferential statistics do?

Answer 1

Inferential statistics make conclusions about a population based on the sample.

Question 2

Once again, what are statistic and parameter?

Answer 2

Statistic is a numerical measure of a sample (mean, variance, std or proportion).
Parameter is numerical measure of a population.

Question 3

Why do we use central limit theorem?

Answer 3

The mean is the most widely used measure in statistics, but an individual extreme value can distort the mean.
To overcome this statisticians have developed the central limit theorem.
This theorem states that:
As the sample size gets large enough, the sampling distribution of the mean can be approximated by a normal distribution.

Large enough is 30.

Question 4

W

What do we use fot the differences in the results from sample to sample?

Answer 4

confidence interval estimate

Question 5

Which distribution do we use when population standard deviation is unknown?

Answer 5

T-distribution