lecture 3 - correlation

Question 1

what are the 5 types of correlation test

Answer 1

1. spearman’s rank
2. pearson’s rank
3. kendall tau
4. biserial
5. phi

Question 2

variable type and symbol for pearson’s

Answer 2

interval/ratio both parametric

r

Question 3

variable type and symbol for spearman’s

Answer 3

ordinal

rs

Question 4

variable type and symbol for kendall tau

Answer 4

ordinal

T

Question 5

variable type and symbol for biserial

Answer 5

nominal - 1 dichotomous and the other has categories

rb

Question 6

variable type and symbol for phi

Answer 6

both dichotomous

φ

Question 7

define dichotomous

Answer 7

has 2 possible answers e.g 1 or 0 which represents yes or no

Question 8

correlation measures…

Answer 8

the strength and direction of the relationship between 2 variables - bivariate analysis

Question 9

correlation coefficient

Answer 9

a single value between -1 and 1

Question 10

descriptions of correlation coefficient

Answer 10

1 = perfect positive correlation
-1 = perfect negative correlation
0 = no correlation
(-)0.3 - (-)0.8 = low correlation 
(-)0.8 + = high correlation

Question 11

we reject the null hypothesis when…

Answer 11

the r value is above the p value

Question 12

define monotonic dataset

Answer 12

with the increase/decrease of one variable, so does the other

Question 13

what is a concordant pair

Answer 13

number of larger rankings below a rank

Question 14

what is a disconcordant pair

Answer 14

number of smaller rankings below a rank

Question 15

when testing significance, biserial always uses a…

Answer 15

2 tailed test

Question 16

in the phi correlation test how many df is there?

Answer 16

always 1