Statistics: Inferential & Descriptive (AQA A Level Psychology)

A study into the relationship between recreational screen time and academic achievement was conducted. Students were asked to self-report the number of hours spent watching TV, playing on their mobile phones or video games (daily recreational screen time) and their end-of-year test performances (academic performance).

The results of the study are shown in Figure 2.

Which of the following correlation co-efficients best describes the data represented in Figure 2?

A study into the relationship between recreational screen time and academic achievement was conducted. Students were asked to self-report the number of hours spent watching TV, playing on their mobile phones or video games (daily recreational screen time) and their end-of-year test performances (academic performance).

The results of the study are shown in Figure 2.

Figure 2 The relationship between daily recreational screen time and academic performance

Identify the type of graph shown in Figure 2 and explain why this is an appropriate graph to use for the data collected.

A study into the relationship between recreational screen time and academic achievement was conducted. Students were asked to self-report the number of hours spent watching TV, playing on their mobile phones or video games (daily recreational screen time) and their end-of-year test performances (academic performance).

The results of the study are shown in Figure 2.

Figure 2 The relationship between daily recreational screen time and academic performance

Explain why it would not be appropriate for the researchers to conclude that increased recreational screen time reduces academic performance.

A psychologist reads a review of a meta-analysis confirming the relationship between recreational screen time and academic performance.

What is meant by the term meta-analysis?

The results obtained from the experiment are summarised in Table 2.

Table 2 Descriptive statistics for the test performance scores for Group A and Group B

Using the data in Table 2, explain how the distribution of scores in Group A differs from the distribution of scores in Group B.

The results obtained from the experiment are summarised in Table 2.

Table 2 Descriptive statistics for the test performance scores for Group A and Group B

What do the mean and standard deviation values in Table 2 suggest about the effect of the recreational screen time on test performance? Justify your answer.

The results obtained from the experiment are summarised in Table 2.

Table 2 Descriptive statistics for the test performance scores for Group A and Group B

The psychologist wanted to test the statistical significance of the data.

Identify the most appropriate choice of statistical test for analysing the data collected and explain three reasons for your choice in the context of this study.

In 1987, a survey of 1000 young people found that 540 said they smoked cigarettes, whilst 460 said they did not. In 2017, a similar survey of another 1000 young people found that 125 said they smoked cigarettes, whilst 875 said they did not.

Which statistical test should be used to calculate whether there is a significant difference in reported smoking behaviour between the two surveys? Give three reasons for your answer.

Table 2 Improvement in happiness scores

The researcher decided to use the Sign Test to see whether there was a significant difference in the improvement in the scores between the two groups at the 5% level of significance.

Calculate the value of S in this study. Show your workings.

Table 3 Table of critical values of the sign test (S)

Significance is shown if the calculated value of S is equal to or less than the critical value.

Explain whether or not there was a significant difference in the improvement in the scores between the two groups.

A psychology teacher read the researcher’s study on sport and happiness. She considered whether setting group tasks could improve her students’ level of happiness. She decided to conduct an independent groups experiment with 30 students taking A-level Psychology using the same happiness questionnaire.

Suggest an appropriate statistical test the psychology teacher could use to analyse the data. Justify your choice of test.

A researcher studying depression wanted to see whether or not there was a relationship between level of self-esteem and negative schema score. She constructed two questionnaires and asked ten people who had been diagnosed with depression to complete them.

One questionnaire measured the participant’s level of self-esteem. A low score (out of 50) indicated low self-esteem.

The other questionnaire measured whether the participant showed evidence of negative schema. A low score (out of 50) indicated evidence of negative schema. The two sets of results for each participant are shown in the table below.

Table 1 Self-esteem score and negative schema score for each patient

Draw a suitable graphical display to represent the data in Table 1. Label your graph appropriately.

A researcher studying depression wanted to see whether or not there was a relationship between level of self-esteem and negative schema score. She constructed two questionnaires and asked ten people who had been diagnosed with depression to complete them.

One questionnaire measured the participant’s level of self-esteem. A low score (out of 50) indicated low self-esteem.

The other questionnaire measured whether the participant showed evidence of negative schema. A low score (out of 50) indicated evidence of negative schema.

The two sets of results for each participant are shown in the table below.

Table 1 Self-esteem score and negative schema score for each patient

With reference to level of measurement, explain why Spearman’s rho is an appropriate statistical test for this data.

A researcher studying depression wanted to see whether or not there was a relationship between level of self-esteem and negative schema score. She constructed two questionnaires and asked ten people who had been diagnosed with depression to complete them.

One questionnaire measured the participant’s level of self-esteem. A low score (out of 50) indicated low self-esteem.

The other questionnaire measured whether the participant showed evidence of negative schema. A low score (out of 50) indicated evidence of negative schema.

The two sets of results for each participant are shown in the table below.

Table 1 Self-esteem score and negative schema score for each patient

Estimate the correlation coefficient most likely to result from analysis of the data in Table 1

The correlation coefficient would be approximately

Julia decided to record how many hours her baby slept for in the day and in the night for one week.

Table 1 The number of hours slept in the day and the number of hours slept in the night over one week

Calculate the mean number of hours slept in the night. Show your workings.

Give your answer to two significant figures

Julia decided to record how many hours her baby slept for in the day and in the night for one week.

Table 1 The number of hours slept in the day and the number of hours slept in the night over one week

Explain one reason why the mean is the most appropriate measure of central tendency for this set of data.

A psychologist was reading an article about typical dream themes in adults.

Figure 2 shows the main dream themes identified in the article.

Figure 2 Main dream themes

Using Figure 2, estimate the percentage of dreams that were reported to be about being chased.

The psychologist was interested in finding out whether dream themes differed between males and females, particularly in terms of social interaction. She decided to conduct a pilot study. Twenty undergraduate students (8 male and 12 female) volunteered for the study. For a six-week period the students were interviewed at 9 am each morning when they arrived at university. Interviewers, who did not know the purpose of the study, carried out and recorded the dream interviews.

The interviews produced qualitative data.

What is meant by qualitative data? Give one strength of collecting qualitative data in this study.

When comparing the data for males and females, the psychologist found that there was a difference in the proportion of friendly and aggressive social interactions. This is shown in Table 2.

Table 2 Percentage of friendly and aggressive social interactions in dreams reported by males and females

A total of 375 dreams reported by males included social interaction. Use the data in Table 2 to calculate how many of these dreams reported by males were classified as aggressive. Show your workings.

When comparing the data for males and females, the psychologist found that there was a difference in the proportion of friendly and aggressive social interactions. This is shown in Table 2.

Table 2 Percentage of friendly and aggressive social interactions in dreams reported by males and females

Draw a suitable graphical display to represent the data in Table 2. Label your graph appropriately.

The psychologist collated the responses of all the participants over the two-week period and calculated the mean and standard deviation for each condition.

Table 3 Mean number of nightmares reported and the standard deviation for each condition

What do the mean and standard deviation values in Table 3 suggest about the effect of the type of film watched on the occurrence of nightmares? Justify your answer

The psychologist collated the responses of all the participants over the two-week period and calculated the mean and standard deviation for each condition.

Table 3 Mean number of nightmares reported and the standard deviation for each condition

The psychologist found that the difference in the number of nightmares reported in the two conditions was significant at p<0.05.

Explain what is meant by ‘significant at p<0.05’ in the context of this experiment.

A psychologist investigated cognitive processing in two groups of people with schizophrenia. People in Group A showed positive symptoms of schizophrenia and people in Group B showed negative symptoms of schizophrenia. Each person completed a cognitive task and was given an overall score. The psychologist then calculated average scores for each group. The results are shown in Table 2 below.

Table 2

Using the data in Table 2, explain how the distribution of scores in Group A differs from the distribution of scores in Group B.

A psychologist investigated perception of foods in two groups of people. People in Group A were on a calorie-counting diet and people in Group B were on a low-fat diet. Each person completed a perception task and was given an overall score. The psychologist then calculated average scores for each group. The results are shown in Table 3 below.

Table 3

Using the data in Table 3, explain how the distribution of scores in Group A differs from the distribution of scores in Group B.   

In an experiment, researchers arranged for participants to complete a very personal and embarrassing questionnaire in a room with other people. Each participant was tested individually. The other people were confederates of the experimenter.

In condition 1: the confederates completed the questionnaire.

In condition 2: the confederates refused to complete the questionnaire and asked to leave the experiment.

The researchers tested 15 participants in condition 1, and 15 different participants in condition 2.

The researchers recorded the number of participants who completed the questionnaire in each condition.

Identify the type of data in this experiment. Explain your answer.

In an experiment, researchers arranged for participants to complete a very personal and embarrassing questionnaire in a room with other people. Each participant was tested individually. The other people were confederates of the experimenter.

In condition 1: the confederates completed the questionnaire.

In condition 2: the confederates refused to complete the questionnaire and asked to leave the experiment.

The researchers tested 15 participants in condition 1, and 15 different participants in condition 2.

The researchers recorded the number of participants who completed the questionnaire in each condition.

In order to analyse the difference in the number of participants who completed the questionnaire in each condition, the researchers used a chi-squared test.

Apart from reference to the level of measurement, give two reasons why the researchers used the chi-squared test.

The calculated value of chi-squared in the experiment described on page 2 is 3.97

Table 1: Critical values for the chi-squared test

The calculated value of chi-squared should be equal to or greater than the critical value to be statistically significant.

With reference to the critical values in Table 1, explain whether or not the calculated value of chi-squared is significant at the 5% level.

A researcher wants to investigate the effectiveness of physiotherapy in the recovery of stroke patients with brain damage. Carers of stroke patients will be sent questionnaires to produce quantitative data.

Explain one disadvantage of obtaining quantitative data in this study.

Write one question that could be used in the researcher’s questionnaire to produce quantitative data and one question that could be used in the researcher’s questionnaire to produce qualitative data.

Table 1 Mean number of seconds taken to complete the 400m run and the standard deviation for both conditions

Explain why a histogram would not be an appropriate way of displaying the means shown in Table 1.

Table 1 Mean number of seconds taken to complete the 400m run and the standard deviation for both conditions.

Name a more appropriate graph to display the means shown in Table 1. Suggest appropriate X (horizontal) and Y (vertical) axis labels for your graph choice.

Table 1 Mean number of seconds taken to complete the 400m run and the standard deviation for both conditions.

What do the mean and standard deviation values in Table 1 suggest about the participants’ performances with and without music? Justify your answer.

Calculate the percentage decrease in the mean time it took participants to run 400 metres when listening to music. Show your workings. Give your answer to three significant figures.

The researcher used a directional hypothesis and analysed the data using a related t-test. The calculated value of t where degrees of freedom (df) = 9 was 1.4377. He decided to use the 5% level of significance.

Table 2 Table of critical values of t

Calculated value of t must be equal to or greater than the critical value in this table for significance to be shown.

Give three reasons why the researcher used a related t-test in this study and, using Table 2, explain whether or not the results are significant.

A psychologist is investigating causes of aggressive behaviour. She interviews teenagers who have been in trouble at school. She asks them to describe their family and early childhood, recording everything that they say. She also looks at information in the teenagers’ school reports.

Referring to this investigation, explain the difference between primary and secondary data.  

A psychologist is investigating causes of offending. She interviews offenders who are in prison for violent crime. She asks them to describe their family and early childhood, recording everything that they say. She also looks at information in the
offenders’ court and prison reports.

Referring to this investigation, explain the difference between primary and secondary data.

A psychologist is investigating causes of addiction to gambling. She interviews people attending debt counselling for problem gamblers. She asks them to describe their family and early childhood, recording everything that they say. She also looks at information in the gamblers’ debt counsellor reports.

Referring to this investigation, explain the difference between primary and secondary data.