Nancy carried out an experiment to see the effects of sensory deprivation on the number of hallucinations participants reported. Participants were split into two groups: - Condition A: Participants had no sensory information for 10 minutes. - Condition B: Participants had no sensory information for 60 minutes. Nancy totalled the number of hallucinations each participant reported. She then carried out a Mann-Whitney U test on her data. (a) State two reasons why Nancy selected a Mann-Whitney U test to use on her data. (b) Nancy’s results are shown in Table 1. Complete Table 1 and calculate the Mann-Whitney U for the data in Table 1. You must give your answer to one decimal place.

A-Level AQA Psychology Research Methods: Nancy carried out an experiment

Nancy carried out an experiment to see the effects of sensory deprivation on the number of hallucinations participants reported - AQA - A-Level Psychology - Question 3 - 2019 - Paper 2

Question 3

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Nancy carried out an experiment to see the effects of sensory deprivation on the number of hallucinations participants reported. Participants were split into two gr... show full transcript

Worked Solution & Example Answer:Nancy carried out an experiment to see the effects of sensory deprivation on the number of hallucinations participants reported - AQA - A-Level Psychology - Question 3 - 2019 - Paper 2

Step 1

State two reasons why Nancy selected a Mann-Whitney U test to use on her data.

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Answer

Nancy was investigating differences between two independent groups: those with 10 minutes of sensory deprivation and those with 60 minutes.
The data collected is ordinal, making the Mann-Whitney U test suitable for the analysis.

Step 2

Complete Table 1 and calculate the Mann-Whitney U for the data in Table 1.

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Answer

To complete Table 1, we need to rank the values for both conditions.

Condition A:

0 (Rank 1)
0 (Rank 2)
4 (Rank 4)
4 (Rank 5)
6.5 (Rank 6)

Total Rank for Condition A = 1 + 2 + 4 + 5 + 6.5 = 18.5

Condition B:

3 (Rank 6.5)
3 (Rank 6.5)
7 (Rank 8)
10 (Rank 10)

Total Rank for Condition B = 6.5 + 6.5 + 8 + 10 = 31

To calculate U:

Total Rank for Condition A = 17.5
Total Rank for Condition B = 37.5

Using the Mann-Whitney U formula: $U_a = n_a n_b + \frac{n_a(n_a + 1)}{2} - R_a$ where: n_a = 5 (number of participants in Condition A) n_b = 5 (number of participants in Condition B) R_a = Total Rank for Condition A = 17.5

Calculating U_a: $U_a = 5 \times 5 + \frac{5(5 + 1)}{2} - 17.5$ $U_a = 25 + 15 - 17.5 = 22.5$

For U_b: $U_b = n_a n_b - U_a$ $U_b = 5 \times 5 - 22.5 = 2.5$

Thus, the U values are:

$U_a = 22.5$
$U_b = 2.5$

The smaller value of U is 2.5, which is the required answer.

Nancy carried out an experiment to see the effects of sensory deprivation on the number of hallucinations participants reported - AQA - A-Level Psychology - Question 3 - 2019 - Paper 2

Worked Solution & Example Answer:Nancy carried out an experiment to see the effects of sensory deprivation on the number of hallucinations participants reported - AQA - A-Level Psychology - Question 3 - 2019 - Paper 2

State two reasons why Nancy selected a Mann-Whitney U test to use on her data.

Complete Table 1 and calculate the Mann-Whitney U for the data in Table 1.

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