An introduction to estimating how many participants/observations you may need

Question 1

what are the two main reasons you will employ the statistical analysis of data

Answer 1

estimation

hypothesis testing

Question 2

what are 2 common types of estimations

Answer 2

frequency

means

Question 3

define hypothesis testing

Answer 3

formal statistical testing of a theory.

Question 4

define null hypothesis

Answer 4

No effect, no difference between groups

Question 5

define alternative hypothesis

Answer 5

An effect, a difference between groups

Question 6

what p value shows significance

Answer 6

p <0.05

Question 7

why does a confidence interval show

Answer 7

If 95% confidence interval does not include the null estimate (0) then your estimate is significantly different to the null (at p<0.05)

Question 8

how you you estimate the effect of something

Answer 8

ODDS RATIO (EFFECT)

Question 9

EQUATION FOR ODDS RATIO

Answer 9

exposed/ not exposed (within group)

Question 10

EQUATION FOR ODDS RATIO IN 2 GROUPS

Answer 10

odds of exposed / odds of not exposed

Question 11

what value does the confidence interval contain

Answer 11

(true value)

Question 12

what value must the confidence interval not contain

Answer 12

1 (odds raio : 1 = no effect)

Question 13

why are larger sample sizes better to use

Answer 13

that ‘the effect seen is less likely to be due to chance’

Question 14

define confidence interval

Answer 14

a range of values so defined that there is a specified probability that the value of a parameter lies within it.