4.3.7 applying statistical techniques

Question 1

correlation coefficient

Answer 1

measure of how closely 2 sets of data are correlated - value of 1 means perfect correlation

Question 2

standard deviation

Answer 2

measure of spread around mean

Question 3

students t-test

Answer 3

test used to compare 2 means

Question 4

what does a low standard deviation imply

Answer 4

data has a narrow range & the points are closely grouped to the mean - could indicate greater reliability

Question 5

what does a high standard deviation imply

Answer 5

data points have a larger range & are less well grouped - may indicate lower reliability

Question 6

formula for standard deviation

Answer 6

pg 290 in textbook

Question 7

what do these symbols mean in the standard deviation equation
s
x
x̄
n

Answer 7

s = standard deviation
x = individual value
x̄ = mean value
n = number of data points

Question 8

first thing when conducting a student’s t-test

Answer 8

state a null hypothesis that there’s no significant difference between the means of these 2 sets of data
–> the student’s t-test measures whether we can reject/must accept it

Question 9

formula for students t-test & meaning of each symbol

Answer 9

pg. 290 of textbook

Question 10

degrees of freedom

Answer 10

defined as number of values in a statistical calculation which are free to vary

Question 11

what do we use the result of the student’s t-test for

Answer 11

compare the degrees of freedom to table of t-values

Question 12

formula used to calculate correlation coefficient

Answer 12

spearman’s rank correlation

Question 13

formula for spearman’s rank correlation & meaning of each symbol

Answer 13

pg 291 of textbook

Question 14

what must we state for spearman’s rank correlation

Answer 14

null hypothesis

Question 15

what table do we use to assess whether the value of Rs indicates a correlation

Answer 15

table of critical values