b) Table: Extract from table of critical values from the Wilcoxon signed ranks test



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Q1. 

(a)    The psychologist was also interested in the effects of a restricted diet on memory functioning and he expected memory to become impaired. The psychologist’s hypothesis was that participants’ scores on a memory test are lower after a restricted diet than before a restricted diet. He gave the volunteers a memory test when they first arrived in the research unit and a similar test at the end of the four-week period. He recorded the memory scores on both tests and analysed them using the Wilcoxon signed ranks test. He set his significance level at 5%.

His calculated value was T = 53.

State whether the hypothesis for this study is directional or non–directional.



(1)

(b)     Table: Extract from table of critical values from the Wilcoxon signed ranks test

 

 

Level of significance for a one-tailed test

0.05

0.025

 

Level of significance for a two-tailed test

0.1

0.05

 

N

T≤

 

19

53

46

 

20

60

52

 

21

67

58

 

22

75

65

 

Calculated T must be equal to or less than the critical value (table value) for significance at the level shown

Using the table above, state whether or not the psychologist’s result was significant. Explain your answer.



(3)

(Total 4 marks)


Q2. 

A researcher carried out an experiment to investigate how many numbers could be held in short-term memory. The participants were 15 children and 15 adults. Participants were asked to repeat lists of random numbers, in the correct order, as soon as they were read out by the researcher. For example, when the researcher said, “3, 4, 2, 8” the participant immediately repeated “3, 4, 2, 8”. When the researcher then said,“7, 5, 9, 6, 4” the participant immediately repeated “7, 5, 9, 6, 4”. One number was added to the list each time until participants were unable to recall the list correctly.Each participant’s maximum digit span was recorded.

(a)     Write an appropriate non-directional hypothesis for this experiment.

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(2)

(b)     Explain why the researcher used an independent groups design for this


experiment.

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(2)

(c)        Frequency distribution of the maximum number of digits


        correctly recalled by children and adults

 

Write the mode for each group in the table below.

 

 

Age group

Mode

 

Children

 

 

Adults

 


(2)

(d)     What does the frequency distribution show about the results?

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(3)

(e)     Do the results of this experiment support the findings of other research into


the capacity of short-term memory? Explain your answer.

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(2)

(Total 11 marks)


Q3. 

Psychological research suggests an association between birth order and certain abilities. For example, first-born children are often logical in their thinking whereas later-born children tend to be more creative. A psychologist wonders whether this might mean that birth order is associated with different career choices. She decides to investigate and asks 50 artists and 65 lawyers whether they were the first-born child in the family or not.


(a)     Write a non-directional hypothesis for this study.



(2)

(b)     Identify an appropriate sampling method for this study and explain how the psychologist might have obtained such a sample

The psychologist found the following results:

•        20 of the 50 artists were first-born children

•        35 of the 65 lawyers were first-born children.

She analysed her data using a statistical test and calculated a value of = 2.27. She then looked at the relevant table to see whether this value was statistically significant. An extract from the table is provided below.




Table: Critical values of

Calculated value of must be equal to or exceed the table (critical) values for


significance at the level shown

(3)

(c)     Imagine that you are writing the results section of the report on this investigation. Using information from the description of the study above and the relevant information from the statistical table, provide contents suitable for the results section.

You must provide all of the following:

•        an appropriately labelled contingency table a sketch of an appropriately labelled bar chart

•        identification of the appropriate statistical test with justification for its use

•        identification of an appropriate significance level

•        a statement of the results of the statistical test in relation to the hypothesis.

(12)

(Total 17 marks)


Q4. 

It is thought that colours might affect our performance when carrying out certain tasks. Research in this area has been inconclusive. Some studies have shown that red improves performance but others have found the opposite. It could be that these contradictory results have arisen because red is beneficial only for certain kinds of mental processing. Some psychologists tested this hypothesis in a series of independent-groups design experiments using students at a Canadian university.

The experiments involved computer tasks, with either a red, blue or neutral background appearing on the monitor. The researchers found that participants were better at a word-recall task and a spell-checking task when the screen background was red rather than blue or neutral. However, participants thought of more creative ideas when the screen was blue rather than red or neutral.

The researchers concluded that red is beneficial for tasks that require attention to detail whereas blue aids creativity.

(a)     What were the researchers’ aims in this study?

Imagine that you are writing up the report for this series of experiments.



(2)

(b)     What is the purpose of the introduction section of a report?

A psychological report also contains a discussion section. Researchers are
expected to consider their findings critically and discuss issues such as validity.

(2)

(c)     What is meant by validity?



(1)

(d)     In the discussion section, researchers are also expected to consider any possible applications of their research. Suggest one practical application that might arise from these findings.

In a further experiment, participants were given 20 blue shapes or 20 red shapes. They were then asked to pick 5 shapes and use them to make a toy suitable for a child aged between five and eleven years. They were given a limited time to carry out this task.
Participants given red shapes made toys that independent judges rated to be more practical but less original, whereas participants given blue shapes made more creative toys.

(2)

(e)     Explain why the researchers asked independent judges to rate the toys.



(2)

(f)     Write a set of standardised instructions that would be suitable to read out to


participants in this experiment.

(5)

(Total 14 marks)


Q5. 

A psychologist carried out an experiment using an independent groups design. The psychologist wished to investigate the effectiveness of a strategy for memory improvement. In one condition, participants were taught a memory improvement strategy. In the other condition, participants were not taught this memory improvement strategy. All participants were asked to memorise 10 pictures of familiar objects. For example, the first was a doll, the second was an apple. All participants were then given 50 pictures each, and asked to select the original 10.

The psychologist did a pilot study before carrying out the experiment. The results of the experiment are shown in the table below.

(a)     Write a directional hypothesis for this experiment.

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(2)

(b)     Explain what is meant by an independent groups design.

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(1)

(c)     Explain one strength and one limitation of using an independent groups design.



Strength .......................................................................................................

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Limitation ......................................................................................................

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(4)

(d)     Explain why the psychologist did a pilot study.

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(3)

The mean number of pictures correctly identified and standard
deviations for participants with the memory improvement strategy
and without the memory improvement strategy

 


 

 

With memory
improvement strategy

Without memory improvement strategy

 

Mean

8

7

 

Standard Deviation

2.80

0.29

(e)     What do the standard deviations in the table above tell us about the performance


of the two groups?

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(2)

(Total 12 marks)


Q6. 

Two psychologists investigated the relationship between age and recall of medical advice. Previous research had shown that recall of medical advice tended to be poorer in older patients. The study was conducted at a doctor's surgery and involved a sample of 30 patients aged between 18 and 78 years. They all saw the same doctor, who made notes of the advice that she gave during the consultation.

One of the psychologists interviewed each of the patients individually, immediately after they had seen the doctor. The psychologist asked each patient a set of questions about what the doctor had said about their diagnosis and treatment. The patients' responses were recorded and then typed out. Working independently the psychologists compared each typed account with the doctor's written notes in order to rate the accuracy of the accounts on a scale of 1 – 10. A high rating indicated that the patient's recall was very accurate and a low rating indicated that the patient's recall was very inaccurate.

(a)     The psychologists decided to propose a directional hypothesis. Why was a


directional hypothesis appropriate in this case?

(1)

(b)     Write a suitable directional hypothesis for this investigation.



(3)

(c)     The psychologists were careful to consider the issue of reliability during the


study. What is meant by reliability?

(1)

(d)     Explain how the psychologists might have assessed the reliability of their


ratings.

(3)

(e)     This study collected both qualitative and quantitative data. From the


description of the study above, identify the qualitative data and the quantitative
data.

The psychologists used Spearman's rho to analyse the data from their


investigation. They chose to use the 0.05 level of significance. The result gave
a correlation coefficient of −0.52.

(2)

(f)     Give two reasons why the psychologists used Spearman's rho to analyse


the data.

(2)

(g)     Using the table below, state whether the result is significant or not significant


and explain why.

(2)

Extract from a table of critical values of Spearman's rho (rS)

 


 

Level of significance for a one-tailed test

 

 

0.05

0.01

 

Level of significance for a two-tailed test

 

 

0.10

0.02

 

N=29

0.312

0.433

 

30

0.306

0.425

 

31

0.301

0.418

  Calculated rs must equal or exceed the table (critical) value for significance at the level shown.

(h)     Explain what is meant by a Type 1 error.

(2)

(i)      Use the information in the table above to explain why the psychologists did


not think that they had made a Type 1 error in this case.

(3)

(Total 19 marks)


Q7. 

Dave, a middle-aged male researcher, approached an adult in a busy street. He asked the adult for directions to the train station. He repeated this with 29 other adults.

Each of the 30 adults was then approached by a second researcher, called Sam, who showed each of them 10 photographs of different middle-aged men, including a photograph of Dave. Sam asked the 30 adults to choose the photograph of the person who had asked them for directions to the train station.

Sam estimated the age of each of the 30 adults and recorded whether each one had correctly chosen the photograph of Dave.

(a)     Identify one aim of this experiment.

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(2)

(b)     Suggest one reason why the researchers decided to use a field experiment rather than


a laboratory experiment. ......................................................................................................................

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(2)

(c)     Name the sampling technique used in this experiment. Evaluate the choice of this sampling technique in this experiment.



Sampling technique...................................................................................

Evaluation...................................................................................................

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Extra space...................................................................................................

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(4)

(d)     Identify one possible extraneous variable in this experiment. Explain how this extraneous variable could have affected the results of this experiment.



Extraneous variable....................................................................................

How this extraneous variable could have affected the results of this experiment

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Extra space...................................................................................................

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(4)

(Total 12 marks)


Q8. 

Some studies have suggested that there may be a relationship between intelligence and happiness. To investigate this claim, a psychologist used a standardised test to measure intelligence in a sample of 30 children aged 11 years, who were chosen from a local secondary school. He also asked the children to complete a self-report questionnaire designed to measure happiness. The score from the intelligence test was correlated with the score from the happiness questionnaire. The psychologist used a Spearman’s rho test to analyse the data. He found that the correlation between intelligence and happiness at age 11 was +0.42.

(a)     Write an operationalised non-directional hypothesis for this study.

(2)

(b)     Identify an alternative method which could have been used to collect data about happiness in this study. Explain why this method might be better than using a questionnaire.



(4)

(c)     A Spearman’s rho test was used to analyse the data. Give two reasons why this test was used.



(2)

Extract from table of critical values from Spearman’s rho(rs) test


 

N (number of participants)

Level of significance for a two-tailed test

 

 

0.10

0.05

 

 

Level of significance for a one-tailed test

 

 

0.05

0.025

 

29

0.312

0.368

 

30

0.306

0.362

 

31

0.301

0.356

Calculated rs must equal or exceed the table (critical) value for significance at the level shown.

(d)     The psychologist used a non-directional hypothesis. Using the table above, state whether or not the correlation between intelligence and happiness at age 11 (+0.42) was significant. Explain your answer.

(3)

(e)     Five years later, the same young people were asked to complete the intelligence test and the happiness questionnaire for a second time. This time the correlation was –0.29.

With reference to both correlation scores, outline what these findings seem to show about the link between intelligence and happiness.

(4)

(Total 15 marks)


Q9. 

A researcher investigated whether memory for words presented with pictures was better than memory for words presented without pictures. The researcher used an independent groups design.

In Condition 1, participants were given a limited time to learn a list of 20 words. They were then asked to recall the 20 words in any order.

In Condition 2, participants were given the same time to learn the same 20 words, but this time each word was presented with a picture. For example, the word ‘appleߣ was presented alongside a picture of an apple. They were then asked to recall the 20 words in any order.


(a)     A pilot study is a small-scale investigation carried out before the main study.

Explain why it would be appropriate for this researcher to use a pilot study. In your answer you must refer to details of the experiment given above.

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Extra space ...................................................................................................

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(4)

(b)     State a non-directional hypothesis for this experiment.

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(2)

(c)     Explain two reasons why it was more appropriate to use an independent groups design than a repeated measures design.



Reason 1 ......................................................................................................

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Reason 2 .......................................................................................................

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(4)


The range and median number of words correctly recalled for participants shown words without pictures and for participants shown words with pictures

 


 

 

Condition 1
Words without pictures

Condition 2
Words with pictures

 

Median number of
words correctly recalled

13

16

 

Range

11

13



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