Pearson Edexcel · GCSE · Psychology
Course version: 1PS0 · Version from Sept 2017
Be able to understand and use, including calculations: a. mean, and…
Full specification wording
Data analysis: 11.2.2 Be able to understand and use, including calculations: a. mean, and finding arithmetic means b. median c. mode d. ratios e. fractions f. percentages g. range as a measure of dispersion h. know the characteristics of normal distributions
Psychological data analysis requires calculating and interpreting descriptive statistics.
Checked against the Pearson Edexcel 1PS0 specification (opens in a new tab) on .
- Point 2 of 5
- 4 key terms
Study notes
From the checked teaching notes for this specification point.
The idea
Psychological data analysis requires calculating and interpreting descriptive statistics. Measures of central tendency include the mean (sum of all values divided by the number of values), median (the middle value when data is ordered), and mode (the most frequent value). You must also calculate ratios, fractions, and percentages to compare groups or express proportions. The range (highest value minus lowest value) is used as a measure of dispersion to show data spread. Furthermore, you must know the characteristics of a normal distribution: it forms a symmetrical, bell-shaped curve where the mean, median, and mode all fall at the exact centre, representing how many psychological traits are naturally distributed.
What earns the marks
- Calculate the arithmetic mean, median, and mode from a raw dataset or frequency table.
- Express parts of a whole or comparisons between groups using fractions, percentages, and simplified ratios.
- Calculate the range to determine the dispersion or spread of a set of scores.
- Identify that in a normal distribution, the curve is symmetrical and bell-shaped.
- State that the mean, median, and mode are equal and located at the centre of a normal distribution.
Common mistakes and how to put them right
Forgetting to order the data from lowest to highest before finding the median.
Put it right: Sort the dataset numerically before identifying the middle value.
Confusing the range with the highest value in the dataset.
Put it right: Calculate the range by subtracting the lowest value from the highest value.
Assuming a skewed distribution has the same characteristics as a normal distribution.
Put it right: Only in a normal distribution are the mean, median, and mode perfectly aligned at the centre.
Exam tips
- When calculating the mean, double-check that you have counted the correct number of participants or data points to divide by.
- To simplify a ratio, find the greatest common divisor for both sides, just as you would when simplifying a fraction.
- Memorise the visual shape and the position of the measures of central tendency for a normal distribution, as you may need to identify or draw it.
Try the lesson
The start of the Data analysis: 11.2.2 Be able to understand and use, including calculations: a. mean, and finding arithmetic means b. median c. mode d. ratios e. fractions f. percentages g. range as a measure of dispersion h. know the characteristics of normal distributions lesson, made from checked teaching notes for this specification point.
Have a go first
A psychologist records the number of words recalled by five participants in a memory test. The scores are 12, 7, 9, 15, and 7. What is the median score for this set of data?
Listen
Psychological data analysis requires calculating and interpreting descriptive statistics. Measures of central tendency include the mean (sum of all values divided by the number of values), median (the middle value when data is ordered), and mode (the most frequent value). You must also calculate ratios, fractions, and percentages to compare groups or express proportions. The range (highest value minus lowest value) is used as a measure of dispersion to show data spread. Furthermore, you must know the characteristics of a normal distribution: it forms a symmetrical, bell-shaped curve where the mean, median, and mode all fall at the exact centre, representing how many psychological traits are naturally distributed. A strong answer earns marks for these points. Calculate the arithmetic mean, median, and mode from a raw dataset or frequency table. Express parts of a whole or comparisons between groups using fractions, percentages, and simplified ratios. Calculate the range to determine the dispersion or spread of a set of scores. Identify that in a normal distribution, the curve is symmetrical and bell-shaped. A common slip: Forgetting to order the data from lowest to highest before finding the median. Instead, sort the dataset numerically before identifying the middle value. Exam tip: When calculating the mean, double-check that you have counted the correct number of participants or data points to divide by.
Key words
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Measures of central tendency
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Measures of dispersion
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Data distributions
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Descriptive statistics
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See every definition
- Measures of central tendency
- These include the mean, the median and the mode, which are calculated from psychological data.
- Measures of dispersion
- The range is used as one of these to show the spread of data.
- Data distributions
- A normal distribution forms a symmetrical, bell-shaped curve where the mean, median and mode all fall at the exact centre.
- Descriptive statistics
- Psychological data analysis requires calculating and interpreting these, including measures of central tendency, ratios, fractions and percentages.
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