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A group of psychiatrists conducted research with patients experiencing depression - AQA - A-Level Psychology - Question 3 - 2017 - Paper 2
Question 3
A group of psychiatrists conducted research with patients experiencing depression. They asked the patients to rate their mood every day over a month, using a scale w... show full transcript
Worked Solution & Example Answer:A group of psychiatrists conducted research with patients experiencing depression - AQA - A-Level Psychology - Question 3 - 2017 - Paper 2
Step 1
Calculate the measures of central tendency for the data in Table 1 and complete Table 1 with your answers.
Answer
To calculate the measures of central tendency for the patient mood scores:
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Mean Score: The mean is calculated by summing all the mood scores and dividing by the number of patients:
The mean score is 4.5.
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Median Score: To find the median, we first arrange the scores in ascending order:
| 2 | 3 | 4 | 4 | 5 | 6 | 6 | 7 | 7 | 7 |
Since there are 10 scores (an even number), the median is the average of the 5th and 6th scores:
The median score is 5.5.
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Mode Score: The mode is the score that appears most frequently in the data. From the list, the score 7 appears 3 times, more than any other score:
Therefore, the mode score is 7.
Step 2
Define what is meant by the term 'a measure of dispersion'.
Answer
A measure of dispersion refers to a statistical method used to describe the extent to which data points deviate from the central tendency in a dataset. Measures of dispersion provide insights into the variability or spread of the data. Common measures of dispersion include:
- Range: The difference between the highest and lowest values in the dataset.
- Variance: A measure of how far each number in the set is from the mean and hence from every other number.
- Standard Deviation: Indicates the average distance of each data point from the mean. A high standard deviation indicates that the values are spread out over a wider range, while a low standard deviation indicates that they tend to be close to the mean.
Step 3
Interpret what the two standard deviations tell us about the results.
Answer
The standard deviation is a crucial measure of dispersion that indicates how varied the mood scores are among the patients.
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The standard deviation of 1.43 for patients with depression indicates that their mood scores are relatively close to the mean score, showing less variability among their responses. This suggests that most patients tend to have similar mood scores, falling within 1.43 points of the mean.
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In contrast, the standard deviation of 3.46 for the group of patients without depression suggests greater variability in their mood scores. This means that there is a wider spread in their ratings, with some patients experiencing very different moods compared to the average.
Overall, the higher standard deviation for the control group implies that their mood ratings are more diverse, which may be indicative of varying levels of emotional experiences in the absence of depression.