Descriptive statistics

Question 1

Mean

Answer 1

Arithmetic average

Question 2

Median

Answer 2

Central score in a list of rank ordered scores

Question 3

Mode

Answer 3

Most common or frequently occurring score

Question 4

Mean strength

Answer 4

Unlike the median, which only represents the middle value, a strength of the mean is the most sensitive measure of central tendency

As it is the only measure which is representative of all the scores in the data set

Question 5

Mean limitation 1

Answer 5

The mean can give peculiar outcomes that don’t represent reality (e.g. 2.6 children)

Question 6

Mean limitation 2

Answer 6

Unlike the median, which only represents the middle value, a limitation of the mean is that it is easily distorted by extreme scores

Making it unrepresentative of the majority of the scores in the data set

In such case, the median may be more representative of the data set

Question 7

Median strength

Answer 7

Unlike the mean, which is representative of all the scores in the data set

A strength is that it is not distorted by extreme scores, making it less likely to be biased

Question 8

Median limitation

Answer 8

Unlike the mean, which is representative of all the scores in the data set

Limitation is that it is less sensitive as it only represents the middle of the data set

Question 9

Mode strength

Answer 9

Unlike the mean, which is representative of all the scores in the data set,

a strength is that it is not distorted by extreme scores making it less likely to be biased

Question 10

Mode limitation 1

Answer 10

Unlike the mean, which is representative of all the scores in the data set,

a limit is that it is less sensitive than the mean as it only represents the most frequently occurring score

Question 11

Mode limitation 2

Answer 11

The mode may not appropriate for small data sets in which each score only appears once, as no score appears more than any other

Question 12

Range

Answer 12

Simplest measure of dispersion, which shows the spread of the scores in any data set by subtracting the smallest score from the largest

Larger range suggests more dispersion amongst the scores, as they are widely spread

Smaller range suggests less dispersion amongst the scores, as they are closely spread

Question 13

Standard deviation

Answer 13

More precise measures of dispersion, which shows the spread of the scores in any data set by calculating their average distance from the mean

Larger SD suggests more dispersion amongst the scores, as they are widely spread

Smaller SD suggests less dispersion amongst scores, as they are closely spread

Question 14

Range strength

Answer 14

Very easy to calculate (by simply subtracting the smallest from the largest score in any data set)

Question 15

Range limit 1

Answer 15

Less sensitive than the SD as it doesn’t use al the scores in its calculation of the dispersion

Question 16

Range limit 2

Answer 16

Easily distorted by extreme scores making it unrepresentative of the majority of scores in the data set

Question 17

SD strength

Answer 17

Most precise measure of dispersion as it is the only one to use all of the scores in the data set by measuring their average distance from the mean

Question 18

SD limit

Answer 18

More difficult to calculate than the range,

Question 19

Bar chart to contain

Answer 19

Title: including IV & DV & type of graph drawn

Clearly labelled Y axis

Scale showing the maximum possible value

Accurately presented data

Clearly labelled x axis

Question 20

Calculating a percentage

Answer 20

Divide given score by the total possible score

Multiply by 100

Question 21

Fraction to percentage

Answer 21

Divide top number by bottom number

Multiply by 100

Question 22

Ratios

Answer 22

Find the lowest possible number that both numbers are divisible by

Write these numbers with a colon between them

Question 23

Measures of central tendency

Answer 23

Mean, mode, median

Question 24

Measures of dispersion

Answer 24

Range, standard deviation

Question 25

Discuss a possible implication

Answer 25

What could happen

Give ideas of what the findings could mean for wider society

e.g. are people more likely to want to do something, will the results affect one group of people over others, will there be any positive or negative financial implications for people or the gov

Use number of marks available as an indicator of how many implications you should give and how much detail to add

Question 26

Discuss a possible application

Answer 26

What you should do

Give ideas of what the findings should mean for how society could be changed

E.g. should people be encouraged to do something by the gov, business or in the work place, could the results be used to affect one group of people over others

Use the number of marks available as an indicator of how many applications you should give and how much detail to add

Question 27

Bar chart

Answer 27

Present non-continuous data, which falls into categories

Frequency of event is plotted on the y axis

Use to show test of difference

Columns don’t touch as each show a separate condition

Question 28

Scattergram

Answer 28

Use to show test of correlation

Data points not connected

Trend illustrated by line of best fit

Question 29

Histogram

Answer 29

Present continuous data, which is measured on a continuous scale (e.g. time; age; distance; height; etc..) along x axis

Frequency of event shown on y axis

Columns touch each other as each shows an interval along a continuous scale

Question 30

Frequency polygon

Answer 30

Present continuous data, measured on a continuous scale

Used to show a test of difference when more than 1 set of data needs to be presented