Stats 1

Question 1

name the three steps in hypothesis testing

Answer 1

1) define a null hypothesis
2) compare observed and expected
3) work out probability observed expected difference happened by chance

Question 2

p

Answer 2

significant - reject null hypothesis. unlikely to have happened by chance

Question 3

If an odds value is 1 then do you accept/reject the null hypothesis?

Answer 3

accept

Question 4

How do you determine Chi2 - three steps

Answer 4

a - work out expected ((row total observed x column total observed )/ overall)
b – sum of ((expected- observed)2 / expected)
c – look up P value against table

Question 5

What degree of freedom is

a) Chi2
b) t test

Answer 5

1) 1

2) 2

Question 6

What is important about numbers for the expected count in a Chi2

Answer 6

must be over 5 for it to work

Question 7

What hypothesis test would you do for normally distributed continuous data

Answer 7

t tests

Question 8

Which test for categorical data?

Answer 8

Chi2

Question 9

Which test doesn’t work with unpaired data?

Answer 9

Chi2

Question 10

What do you calculate in an independent t test and how

Answer 10

T value. Use differences between mean. diff/Standard error = T value. Then look up p value sing table

Question 11

What are you looking for with 95% confidence intervals of t test mean values

Answer 11

Do they cross 0? if 0 then no differences between the means so no statistical significance

Question 12

What would you do if your continuous data is not normally distributed?

Answer 12

try log or use none parametric test like mann-whitley

Question 13

When do you use odds ratio

Answer 13

Categorical outcomes

Question 14

when do you use mean difference

Answer 14

continous outcomes