Lecture 8

Question 1

why we use chi-squared test

Answer 1

to test these hypothesis: independence and homogeneity

Question 2

Define homogeneity hypothesis

Answer 2

We ask a question whether the distribution of ONE VARIABLE is the same in TWO (or more) POPULATIONS

Question 3

how the study is designed?homogeneity

Answer 3

the study involves two groups that have been sampled separately, and the responses will address one variable in question

Question 4

define independence test

Answer 4

We ask a question whether there’s an association between TWO VARIABLES in ONE POPULATION

Question 5

how the study is designed? independence

Answer 5

The design of the study involves one group that has been cross-categorized based on responses to two variables.

Question 6

5 basic conditions before chi-square test

Answer 6

• The observation data is independent of each other.
• The data should be expressed in original units (not in percentage or ratio form)
• The data must be drawn randomly from the target population
The sample should sufficiently large

Question 7

when we use Fishers exact test?

Answer 7

sample size is too small;

the smallest expected frequency is below 5

Question 8

Expected frequency

Answer 8

The expected frequency isa probability count that appears in contingency table calculationsincluding the chi-square tes