Test of Proportions Flashcards
What will a test of proportions tell me?
It will tell me whether a sample from a population represents the true proportion from the entire population.
what type of data does a test of proportions use?
categorical data.
A chi-square test is a nonparametric statistic used to determine:
if a distribution of observed frequencies differentiates from theoretically expected frequencies.
The Chi Square Test has 2 primary uses, what are they?
test of goodness of fit and test of independence
what does the test of goodness of fit determine?
if a set of observed frequencies differs from a set of theoretical frequencies.
what does a test of independence determine?
if 2 classification variables are independent of each other.
how do i determine degrees of freedom?
n - 1 (number of groups - 1)
What is our alpha value?
.05
Online, what 2 variables do I need to calculate my critical value?
degrees of freedom and the p - value
What are the 8 steps to the chi square test?
- State the null and alternative hypothesis.
- determine degrees of freedom.
- determine alpha value
- determine the critical value
- calculate expected values
- run chi-square analysis.
- compare results to the critical value
- accept or reject the null hypothesis
Can I accept my null hypothesis if my chi-square result is below my critical value?
yes.
What assumptions have to be made if I want to run a chi-square test?
- The groups are independent of each other
- The value of the cells in the expected count should be 5 or above in at least 80% of the cells.
- No cell should have an expected count of <1
If any of those assumptions that have to be true to run a chi square test are violated (aka not true), what test should we run?
McNemar Test
The McNemar Test is a:
statistcal hypothesis test used when you want to compare proportions between 2 groups that are NOT INDEPENDENT.
If data is sparse, has 2 groups and independent, what test do we run?
Fisherβs Exact Test
