part 3

Question 1

what are measures of central tendency used to give?

Answer 1

they are averages which give he information about the most typical values in a set of data

Question 2

how do you calculate the mean?

Answer 2

add all the values together and divide by the number of scores

Question 3

evaluate the use of the mean

Answer 3

strength
- the most sensitive of al measures because it takes all scores into account

limitation
- can be easily distorted by extreme values

Question 4

how do you calculate the median?

Answer 4

place in order of low to high and find the middle value
if there’s an even number, find the number in between both values

Question 5

evaluate the use of the median

Answer 5

strength
- extreme scores do not effect it and will not distort and very easy to calculate

limitation
- less sensitive than the mean as it doesn’t include all of the scores

Question 6

how do you calculate the mode

Answer 6

the most frequently occurring number
- may be bi-modal meaning there’s 2 modes or multi-modal meaning there’s more than two modes

Question 7

evaluate the use of the mode

Answer 7

strength
- easily calculated

limitation
- crude measure and should be avoided if possible but it can be the only measure that can be used if it’s categories

Question 8

what are measures of dispersion?

Answer 8

based on the spread of scores and tell us how far scores are spread from each other

Question 9

how do you calculate the range?

Answer 9

largest value - smallest value

Question 10

what is shown if the mean value for two sets of scores is the same but the range is different?

Answer 10

the set of values which has the higher value for range shows the scores are more widely spread (more dispersed)

Question 11

evaluate the use of the range

Answer 11

strength-
easy to calculate

limitation
only takes into account the two extreme values so may be unrepresentative of the data as a whole

Question 12

what is standard deviation?

Answer 12

a more precise measure of dispersion and tells us how the mean scores are spread around the mean

Question 13

what is a low standard deviation showing?

Answer 13

the data are tightly clustered around the mean

Question 14

what does a high standard deviation show?

Answer 14

the scores are widely spread and not all the pps were affected in the same way

Question 15

how do you distinguish between a low and high standard deviation?

Answer 15

the larger the standard deviation score, the more widely dispersed from the mean

Question 16

evaluate standard deviation

Answer 16

strenth
- more sophisticated than the range

limitation
- can be distorted by an extreme score

Question 17

what are bar charts used for?

Answer 17

plotting discrete (discontinuous) data which means they do not overlap in any way
==> for exaple, breeds of dogs or what newspapers you read

Question 18

what are histogram used for?

Answer 18

the x-axis doesn’t show discrete data aa it is continuous and there are no gaps between the bars

Question 19

what are line graphs used for

Answer 19

to show change over time or trials

Question 20

what are scattergraphs used for?

Answer 20

shows the relationship between two variables

Question 21

what do normal distributions curves show? (key features)

Answer 21

1. mean, median and mode are all at the exact same midpoint
   2- scores are symmetrical from the midpoint
2. the dispersion of scores on either side of the mid point is consistent ad expressed as standard deviations

Question 22

what does a skewed distribution curve show?

Answer 22

data is not symmetrical and the data clusters towards one end

Question 23

on a skewed distribution curve, what central tendency is always at the peak?

Answer 23

mode

Question 24

what is a left-skewed distribution?

Answer 24

tail is to the left meaning most of the data is towards the right.
- this is due to the mean being affected by extreme scores and so gets dragged to the left

Question 25

what is a right-skewed distribution?

Answer 25

tail is to the right meaning most of the data is towards the left.
- this is due to the mean being affected by extreme scores and so gets dragged to the right

Question 26

is the mean value greater in a left or right skewed distribution?

Answer 26

right-skewed