Descriptive statistics Flashcards

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1
Q

Data

A

The measurements collected from an experiment to illustrate a trend or lack thereof that the IV has on DV

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2
Q

Forms of data can be in

A

Primary or secondary
Quantitative or qualitative
Discrete or continuous
Raw or processed

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3
Q

Primary data

A

Data collected within each condition from an experiment by a researcher

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4
Q

Secondary data

A

Data which already exists and is collected by researchers to analyse

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5
Q

Quantitive data

A

Measurements taken in the form of numbers

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6
Q

Qualitative data

A

Measurements taken in the form of words, descriptions, observations, pictures etc
Not limited by a choice or scale and can not be put into pre set categories

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7
Q

Can qualitative data be processed into quantitate data?

A

Yes then can be analysed

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8
Q

Discrete data

A

Values that can be counted in a scale of fixed and specific values
And there is no in between such as number of people, number of words recounted etc (cannot have half of a word for example)

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9
Q

Continuous data

A

Values that can be counted in a scale of continuous values so can be in between intervals and exist as any value
Such as length, weight and height

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10
Q

Raw data

A

Data collected straight from the experiment which has not been processed
Such as pre making a table for an experiment and inputting values collected

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11
Q

Processed data

A

Data which has been put into graphs and drawing conclusions from it etc

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12
Q

Raw data tables

A

Made before an experiment to input values which will be collected in the experiment
No analysis

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13
Q

Raw data table for repeated measures design

A

All as 1 big column
Participant number down the first column
Then the other columns for scores taken from each condition completed
To show every participant took part in the same condition

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14
Q

Raw data for matched participant/ independent measures design

A

1 table per condition to show each participant took part only once in only 1 condition so no repeating

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15
Q

Descriptive statistics

A

Calculations made straight from raw data collected to sum up and present findings
Or drawing graphs

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16
Q

Measures of central tendency

A

Ways of determining the average of typical score in a set of data :
Mean
Mode
Median

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17
Q

How to calculate mean

A

Total of all scores
—————————————
How many scores there are

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18
Q

Advantages of mean

A

All data is included when calculated so doesn’t ignore any scores

19
Q

Disadvantages of mean

A

An outlier score would skew the mean calculated so wouldn’t represent most of the scores

20
Q

How to calculate median

A

Put in order smallest to largest
Find middle value
If there are 2 middle values then find midpoint of those

21
Q

Advantages of median

A

Not affected by an outlier score so not skewed

22
Q

Disadvantages of median

A

Not helpful if there are not enough values
Not take into account the precise other values so not use all data

23
Q

How to calculate the mode

A

Most common score
Can be more than 1 or none at all

24
Q

Advantages of mode

A

Can be used for qualitative data
Easy to calculate
Not affected by outlier score

25
Q

Disadvantages of mode

A

May not represent all of data in some cases
May not work with a small set of data
Impossible to calculate if all data is different

26
Q

Bar charts

A

A way of representing processed data in an experiment where each condition is separate categories for each bar
Might use central tendency as we are comparing average scores between conditions

27
Q

What to remember when making a bar chart

A

Labelled y axis with specific descriptive statistic eg mean
Which always starts at 0
Title
Accurate data points plotted
Labelled x axis for each condition

28
Q

Measures of dispersion

A

Indicates how far the results will be spread around the typical (central tendency score)
Range
Variance
Standard deviation

29
Q

How to calculate the range

A

Difference in lowest and highest scores
(Optional too add 1 to represent all values that are possible including 0, although either is allowed but be consistent

30
Q

Advantages of the range

A

Easy and quick to calculate for a sense of how dispersed scores are
Shows variety or no variety: small variance shows scores are close together

31
Q

Disadvantages of range

A

Does not give any indication if the distribution is even or clustered around a certain point and if other values are outliers or just less spread out

32
Q

How to overcome the disadvantage of the range?

A

Calculate variance and standard deviation

33
Q

How to display the range on a bar chart

A

A line drawn at each condition shown on the x axis (so inside each bar) which will extend from the smallest value to largest value so length of this line shows the range

34
Q

Variance

A

Indicates how far spread apart the data is form the mean score

35
Q

What does a low variance show?

A

Within that condition, the participants are less spread out from the mean score

36
Q

What does a high variance show?

A

Within that condition, the participants are more spread out from the mean score

37
Q

Why is the variance good?

A

It treats all variations from the mean as the same and therefore takes into account every value
So won’t be affected by outliers

38
Q

How to calculate the variance?

A

Calculate mean score per condition
For each participant score: Mean score - Participant score =d (Might be negative)

All of d² added together
Divide by number of participants in sample

39
Q

Methods of data collection

A

Observation
Correlation
Self report
Physiological measures

40
Q

How to calculate the standard deviation?

A

Square root of the variance

41
Q

Why calculate the standard deviation?

A

Tells us an accurate measure of dispersion in the same scale as the data that we measured

42
Q

Examples of descriptive statistics in terms of calculation

A

Measures of central tendency
Measures of dispersion

43
Q

Descriptive statistics for displaying data

A

Frequency tables (tally charts)
Line graphs
Pie charts
Bar charts
Histograms
Scatter diagrams