QP & MS June 2024
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Paper
Statistics
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Advanced
PAPER 2: Statistical Inference
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P75705RA
©2024 Pearson Education Ltd.
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, Answer ALL questions. Write your answers in the spaces provided.
1 Brenda is a yoga teacher. She is researching the benefits of regular yoga practice on
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reducing eye fatigue.
To carry out her research, Brenda seeks 12 volunteer students, who have never practised
yoga before, to join her yoga classes.
She asks each student to complete a questionnaire before they start her classes.
In her questionnaire, the first question is as follows.
Indicate below your current level of eye fatigue by placing a cross on the line.
A score of 0 indicates no eye fatigue and a score of 10 indicates severe eye fatigue.
0 1 2 3 4 5 6 7 8 9 10
After attending her classes for three months, these 12 students are asked again to
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complete the same questionnaire.
Both scores for the first question, for each of these 12 students, are given in Figure 1
Student A B C D E F G H I J K L
Score before yoga 7.4 6.2 8.8 3.5 5.4 6.3 9.5 4.4 6.3 7.8 3.6 5.0
Score after yoga 4.3 5.0 4.7 3.5 6.7 4.5 5.0 6.2 3.5 2.4 4.8 4.5
Figure 1
Brenda believes that regular yoga practice can reduce the average eye fatigue score.
(a) Making any necessary assumptions, carry out a paired t-test to investigate whether
there is evidence to support Brenda’s belief.
(7)
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, Question 1 continued
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(b) Give two possible sources of bias in this experiment.
(2)
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(Total for Question 1 is 9 marks)
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