Lecture 6 - Inferential Statistics

Question 1

What does significance level usually constitute of?

Answer 1

Significance levels usually constitutes an arbitrary choice:1%, 5%, 10%

Question 2

What is the most important factor to take into account when picking signficance level?

Answer 2

The most important factor to take into account is the effect of error – what happens if we draw the wrong conclusion?

If Type I error is worse than Type II error, consider a 1% significance level

If Type II error is worse than Type I error, consider a 10% significance level

Question 3

What are the two tpes of error we can make when doing an hypothesis test?

Answer 3

There are two types of error we can make when doing a hypothesis test:

Type I error: We reject the null hypothesis when it is in fact true.

Type II error: We fail to reject the null hypothesis when it is in fact false.

Question 4

Example of picking Signifcance level?

Answer 4

Question 5

Example of picking Signifcance level? (Part 2)

Answer 5

Question 6

What is Degrees of freedom?

Answer 6

Question 7

How to use tables for t-distribution?

Answer 7

Question 8

Calculating the standard error with the t-distribition table?

Answer 8

Question 9

Assumptions of the t-distribution?

Answer 9

Question 10

What is a One-Sample t-Test and how do you calculate its degrees of freedom?

Answer 10

A One-Sample t-Test is a statistical procedure used to determine whether the mean of a single sample differs significantly from a known or hypothesized population mean.

df=n−1
Where
𝑛
n is the number of observations in the sample.

Question 11

What are the formulas for the 3 different types of hypothesis test?

Answer 11

Question 12

How to do hypothesis test with proportions?

Answer 12

Use the formula in the red box

Question 13

How do we decide what hypothesis to use?

Answer 13