Flashcards in EDS Deck (130)

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1

## what is nominal data

### categorical data which cant be ordered e.g. gender, blood group

2

## what is ordinal data

### categorical data which can be ordered

3

## what is discrete data

### numerical data which only contains whole numbers

4

## what is continuous data

### numerical data which has no limitations on the value e.g. height or weight

5

## what is prevalence

### the number of people with that condition at that point in time

6

## what is incidence

### the rate of new events in a time period

7

## how do you calculate variance

### sum of squares of residuals/degrees of freedom

8

## how do you calculate degrees of freedom

### sample size - number of constraints

9

## how do you calculate standard deviation

### square root of variance

10

## what is internal validity

### refers to whether the effects observed in a study are due to manipulation of the independent variable and not another factor

11

## what is external validity

### looks at whether the results can be generalised across the whole population

12

## how do you calculate the standard deviate (z score)

### x-mean/SD

13

## between what range of standard deviations from the mean do 68% of the population lie

### -1 and +1

14

## between what range of standard deviations from the mean do 95% of the population lie

### +/- 1.96

15

## between what range of standard deviations from the mean do 99.9% of the population lie

### +/- 3.29

16

## what is pseudoreplication

### where multiple measurements are taken from one individual

17

## what is the standard error of the mean

### the measure of the variability of the distribution of means

18

## how do you calculate SEM

### SD/square root n

19

## how does sample size affect SEM

### greater sample size gives a smaller SEM

20

## how do you calculate 95% confidence internals

### CI = mean +/- (1.96 x SEM)

21

## what is a one tailed hypothesis

### where there is a specified direction

22

## what is a two tailed hypothesis

### where there is no specified direction

23

## what is a type 1 error

### a false postiive

24

## what is the error rate for type 1 errors

### 5%

25

## how does p value affect the type 1 error rate

### high p value increases type 1 error rate

26

## what causes type 1 errors

### publication bias, lower power, poor understanding of statistics, p-hacking

27

## what are type 2 errors

### false negatives (not rejecting the null hypothesis even though its false) - incorrectly concluding that there's no effect

28

## what is the rate of type 2 errors

### 1-power

29

## what is power

### this is the probability of rejecting the null hypothesis when its false

30