Research methods - Chi-Square and intro to stats test

Question 1

what are inferential tests

Answer 1

procedures for drawing logical conclusions about the target population from which samples are drawn

Question 2

what do inferential tests allow

Answer 2

allows researchers to test if there are differences between conditions or associations between conditions, and if those differences/associations are due to chance

Question 3

what do researchers seek to do by carrying out statistical tests

Answer 3

to accept or reject the null hypothesis

Question 4

what decides if a test is parametric or non parametric

Answer 4

depends of the level of data and assumptions about the sample

Question 5

what are the conditions for parametric tests

Answer 5

data must be interval e.g cm, seconds
data that is drawn from a population with a normal distribution, meaning the groups have similar variances

Question 6

what are the conditions for non-parametric tests

Answer 6

do not need to make the assumptions that parametric tests require and data can be nominal e.g gender or ordinal e.g smallest to largest

Question 7

what is the name of the table used to remember stats tests and what does this stand for

Answer 7

N (nominal)
O (ordinal)
I (interval)

I (independent measures) R (repeated measures incl, matched pairs) AC (association/correlation)

Question 8

what is the acronym to remember the stats tests and what does this stand for

Answer 8

Carrots (Chi-Square)
Should (Sign test)
Come (Chi-Square)

Mashed (Mann-Whitney U)
With (Wilcoxon)
Swede (Spearman’s Rho)

Under (Unrelated t test)
Roast (Related t test)
Potatoes (Pearson’s r)

Question 9

what is nominal data

Answer 9

a measure of how many things occur within a category, these categories are mutually exclusive
most basic level of data, only gives superficial info

Question 10

what is the test statistic for Chi-Square

Answer 10

x^2

Question 11

what is the formula for x^2

Answer 11

sum of: (observed frequency - expected frequency)^2/expected frequency

Question 12

what is the formula for expected frequency

Answer 12

row total x column total /grand total

Question 13

what are the steps for completing the Chi-Square test

Answer 13

1) Calculate row, column and grand totals
2) Calculate the expected frequency for each cell if the null hypothesis were true
3) For each cell calculate (expected freq-observed freq)^2 / expected freq
4) Add together to get a calculated value of x^2
5) compare with critical value
6) write a significance statement

Question 14

what must be true for the Chi Square test in order to reject the null hypothesis and get significant results

Answer 14

the calculated value of x^2 must be GREATER than the critical value of x^2 (rule of R)

Question 15

what do you need to find the critical value of x^2

Answer 15

level of significance (5%/0.05)
degrees of freedom - (number of rows-1) x (number of columns -1)

Question 16

what must be included in the significance statement

Answer 16

calculated and critical values, which is greater, are results significant, significance level, degrees of freedom, do we accept or reject null hypothesis, what does this suggest