Flashcards in A2 RESEARCH METHODS- inferential stats- measures of central tendancy/measures of dispersion Deck (40):

1

## what does inferential stats allow?

### psychologists to draw conclusions based on probability that a particular pattern of results could have arisen by chance

2

## what if unlikely that results occurred by chance?

### described as significant

3

## in most research what do psychologists say?

### if results are sig if probability occurred by chance is less than 0.05

4

## how is p less than 0.05 written?

### p,0.05

5

## what is it meant in other words?

### risk that results occurred by chances is less than 0.05 / 5% so we can be more than 95% sure that they were due to effect of iv and dv

6

## if psychologists want to be more significant what do they do?

### p

7

## what do inferential tests determine?

### likelihood that results due to chance.

8

## what do they produce?

### observed value

9

## what must an observed value be compared to?

### critical value which comes from table

10

## in spearmans rho and chi square tests the observed value must be?

### must be greater than critical to be sig

11

## in mann whitney and wilcoxon tests the observed value must be?

### less than critical value for result to be sig

12

## what are the two types of errors?

### type 1 & type 2

13

## what are type 1 errors?

### rejecting a null hypothesis that is true and accepting a experimental hyp that is not true. happens when level of signifcance too high e.g 10%

14

## what are type 2 errors?

### accepting null when not true and rejecting experimental that is true -happens when sig too low e.g 1%

15

## what are the types of levels of measurements?

### nominal, ordinal, interval

16

## what is nominal data?

### data in separate categories such as grouped into tall,medium,short. names of categories are simply labels

17

## what is ordinal data?

### data ordered/ranked but gap btw each item not the same e.g rating how happy u are on scale of 5

18

## what is interval data?

### data measured using specific units of measurement which are equally spaced apart such as measuring height in cm

19

## what are the types of inferential tests?

###
spearmans rho,

chi square

mann whitney u test

wilcoxon test

20

## when would you use spearmans rho?

### testing for correlation, data is ordinal interval or ratio, there are no or few tied ranks

21

## when would you use chi square?

### data is nominal, no other test suitable!

22

## when would you use mann whitney?

### testing for difference, indepdant groups design, data ordinal interval or rational

23

## when would you use wilcoxon?

### testing for difference, there is repeated measures design, data is ordinal interval or ratio

24

## what are the measures of central tendancy?

###
mean

median

mode

25

## what is mean?

### found by adding up all values and dividing by values

26

## advantages of mean?

### makes use of all values in data set

27

## disadvantages of mean?

### can be misrepresentative if there are extreme values

28

## what is median?

### middle value of ordered value could do number of scores + 1 / 2 if there are even number of scores then middle = 10 + 1 /2

29

## advantages of median?

### not affected by extreme values

30

## disadvantages of median?

### not as sensitive as mean as not all values reflected

31

## what is mode?

### most common value- remeber may be more than one mode should report all

32

## advantages of mode?

### easy to calculate provides direct info

33

## disadvantages of mode?

### not useful when there are several modes

34

## what are the measures of dispersion?

###
range

standard deviation

35

## what is range?

### difference btw highest and lowest score in a data set

36

## advantage of range?

### easy to calculate and provides direct info

37

## disadvantage of range?

### affected by extreme values doesnt consider number of values in data set

38

## what s standard deviation?

### assesses the spread of data around mean to show the amount of variation in a data set. a greater standard devation means there is greater variation in data set

39

## advantage of standard deviation?

### more precise measure of dispersion as all values taken into account

40