Hi I'm Heejin
If you wanna know chi-square test?
Don't hesitate to watch this video -> chi-square test calculation
- What does this test show us
- How do we calculate and interpret it
- When would do we use it
- When
Let's say there is 100 students
if we gonna select randomly 20 students from them
How many female students are in there?
The probablity of this is 50:50.
But the result is different with our thought.
Tada! [female:14 and male:6] is the result.
Than, how do we suppose the 50:50 probablity is correct?
How does this evidence stack up that 50:50?
1. What does this test show us
We want to 'claim' below line
- observed = predicted
if (P = 0.5) is correct, we will assume that 10 students are female be correct. But the evidence can't show us the prediction is right.
So, chi-square test is needed in this situation.
It can prove this claim whether is right or not.
2. How do we calculate and interpret it
If you got a value in chi-square, you should refer to this table to interpret this value.
- df = degree of freeom
What is df?
: if 'n' position is available to seat, the last one has no choice to select where to seat.
ex) Think categories, 'female or male' is what we're looking for.
So there is 2 position available, and hence, df is 1.
Does this data support the claim and null hypothesis?
3. When would do we use it
Hypothesis
H0 (null hypothesis)
: This is the hypothesis where things are happening as expected
H1 (alternative hypothesis)
: This is a claim where if you have evidence to back up that claim, that would be 'new' news.
