M3 - t-test

Question 1

One-sample

Answer 1

Tests whether the mean of a normally distributed population is different from a specified value.

Question 2

Two-sample

Answer 2

Tests whether the means of two populations are significantly different from one another

Question 3

Two-sample Paired

Answer 3

Each value of one group corresponds directly to a value in the other group

Example: Comparing the heart rate of Mr Blackmore before and after he loses 15 kilograms while walking at a consistent speed on a treadmill.

Question 4

Two-sample unPaired

Answer 4

• the two populations are independent

Example: Comparing the bone density of twins, one group which goes to space and the other group stays on Earth.

Question 5

one tail test

Answer 5

values of the sample which cause rejection of the null hypothesis fall in only one tail of the sample

Question 6

two tail test

Answer 6

the sample can fall in either end of the left or right tail and still cause rejection of the null hypothesis

Question 7

example of one vs two tail test

Answer 7

if we are investigating only if right hands are faster than left hands we do one tail but is investigating if right hands were either faster or slower we used two tail

Question 8

Assumptions

Answer 8

refer to the conditions or criteria that must be met for the validity of the test being selected. This ensures the conclusions drawn from the analysis are reliable.

Question 9

assumptions for a t-test

Answer 9

• data is continuous: it must not be categorical
• random sampling: data must be randomly selected from a population to avoid bias
• normality: the data should be approximately normally distributed
• similar variance: variance of data (spread of the data) should be relatively equal
• appropriate sample size: This should be approximately 30 or more per group if possible. This should allow for normally distributed data to become evident and supports similar variance