Inferential Statistics | Edexcel Psychology A2

[Maximum number: 6]

Daisy wanted to use a correlational research method to investigate whether aggression and exposure to media violence were linked. She decided to use a questionnaire to gather her data.

(a)

Daisy completed her investigation and analysed her data. She scored responses to the questionnaires for aggression, with a score of 20 indicating very aggressive. Daisy also scored the exposure to media violence, with a score of 20 indicating significant exposure to media violence.

Calculate the Spearman's rank correlation coefficient for the data gathered by Daisy by completing Table 2.

The formulae and statistical tables can be found at the front of this paper.
You must show your working out and give your answer to three decimal places.

Table 2 Space for calculations

Spearman's rank correlation coefficient

[ 4 ]

Credit one mark for a correct completion of column d Credit one mark for a correct completion of column d ${ }^{2}$ Credit one mark for a correct substitution into the equation Credit one mark for a correct answer to three decimal places = 0.643

For example;
\begin{tabular}[t]{|l|l|l|l|l|l|}
\hline Score for
aggression
out of 20

Rank 1

Score for
exposure
to media
violence
out of 20

Rank 2

d

$\boldsymbol{d}^{\mathbf{2}}$

9

4

10

4

0

15

7

13

6

1

14

6

18

8

-2

8

3

5

1

2

19

8

14

7

1

3

1

7

2

-1

11

5

9

3

2

4

2

11

5

-3

Total for $\boldsymbol{d^{\boldsymbol{2}}}$ }

\end{tabular}
$1-\frac{6 \Sigma d^{2}}{n\left(n^{2}-1\right)}=1-\frac{144}{8(64-1)}=1-\frac{144}{504}=1-0.286=\mathbf{0. 7 1 4}$

Look for other reasonable marking points.
\end{tabular}

(4)

(b)

Interpret the Spearman's rank correlation coefficient from 8(c) in terms of the strength and direction for Daisy's investigation.

[ 2 ]

Edexcel A-Level Psychology A2 9.1.12 Inferential Statistics Questions

Exam points

Edexcel A-Level Psychology A2 9.1.12 Inferential Statistics Questions question 1

Question (a)

Question (b)