# Descriptive statistics

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• Created by: Steff06
• Created on: 10-05-16 12:07
What are descriptive statistics used for?
Method of summarising and analysing data to allow us to draw conclusions from it. Summarises and describes the data.
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What are the 2 main ways of summarising data?
Measures of central tendency and measures of dispersion.
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What are measures of central tendency?
Mean, median, mode.
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What is the mean value and how is it calculated?
Mean is an average that indicates the typical score in a set of data. Calculated by adding all of the scores in each condition and dividing by total number of scores.
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What is a strength of the mean?
Takes all scores into account.
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What are weaknesses of using the mean?
Can be misleading if there are extreme values. Cannot be used with nominal data.
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What is the median and how is it calculated?
The middle value. Calculated by finding the mid-point in a set of data by placing all values in one condition in order and finding the mid-point.
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What is a strength of using the median?
More useful measure than the mean when there are extreme values.
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What are the weaknesses of using the median?
Cannot be used with nominal data and not all of the scores are taken into account.
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What is the mode and how can we calculate it?
The most common value in a set of values. Find the most common.
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What is a strength of using the mode?
Can be used with nominal data.
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What is a weakness of using the mode?
Used less as it doesn't tell us anything about other scores in the distribution and is not an average.
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What do measures of dispersion show?
Shows us the spread of a set of data.
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What are examples of measures of dispersion?
Range, standard deviation
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What is the range?
The difference between the smallest and largest value in a set of scores.
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When do we usually use the range?
When we used the median as the measure of central tendency.
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What is a weakness of using the range?
It only takes into account the highest and lowest scores.
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What does standard deviation tell us?
Tells us on average, how much the scores differ from the mean.
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When do we usually use standard deviation?
When we have used the mean as our measure of central tendency.
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What is a strength of standard deviation?
It takes account of every score.
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What does it mean if the standard deviation of a group of scores is large?
The scores are widely distributed with many scores occurring a long way from the mean.
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What does it mean if the standard deviation is small?
Most scores occur very close to the mean.
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What can we use graphs for?
To create a graphical display of descriptive statistics.
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## Other cards in this set

### Card 2

#### Front

What are the 2 main ways of summarising data?

#### Back

Measures of central tendency and measures of dispersion.

### Card 3

#### Front

What are measures of central tendency?

### Card 4

#### Front

What is the mean value and how is it calculated?

### Card 5

#### Front

What is a strength of the mean?