Fakedata & Fraud (1998) carried out research to test the theory that women are better at recognising faces than men. They showed women and men a series.

Correlational Analysis

Fakedata & Fraud (1998) carried out research to test the theory that women are better at recognising faces than men. They showed women and men a series of 60 photographs of adults. Half of the photographs were of people they had been at school with and half were not. The pps were asked to state whether or not they recognised the people in the photographs. The participants were scored +1 for each photograph they correctly identified as being a person they were at school with. The frequency histogram below shows the results of the experiment.

Starter

1. What was the size of the sample of men and women used in the experiment?

2. What was the approximate range of scores for women and for men?

90

12

Learning Objectives:1) To develop an understanding of correlational data analysis.

Success Criteria:1) Read through the booklet and make notes about the strengths and weaknesses of correlational analysis on page 17.2) Carry out your own correlational analysis.

Lets learn about correlations

Tasks

1. Read through the booklet (page 17) about correlations

2. Sketch the three types of correlation

3. Problems with correlational analysis…

More cat owners 'have degrees' than dog-lovers

People who own a cat are more likely to have a university degree than those with a pet dog, a study by Bristol University suggests. A poll of 2,524 households found that 47.2% of those with a cat had at least one person educated to degree level, compared with 38.4% of homes with dogs. The study said longer hours, possibly associated with better qualified jobs, may make owning a dog impractical. It also found that UK pet ownership was much higher than previously thought.

Dr Murray, whose post is funded by the Cats Protection charity, said researchers hoped to repeat the study using the results of the 2011 census to get a clearer idea of trends in UK pet ownership.

Correlation coefficients

0No correlation

-1 perfect negative

correlation

+1 perfect positive

correlation

Weak Weak Strong Strong

We calculate a coefficient between -1 and +1

The closer to 1 (+ or -) the stronger the relationship

Here are some scattergrams and the correlation coefficients that correspond to them. Try matching them up.

+0.91 +0.66 -0.61 +0.22 -0.85 +0.01

Task

Make some notes about the strengths and weaknesses of correlational analysis on page 17 of your booklet.

Grab some graph paper and answer the past paper question at the bottom of page 17.

Extension task

You are going to carry out your own correlational analysis

You are going to plot the relationship between stress at school and absence What is the hypothesis?

You need to ask 20-30 students how stressed they feel currently about school and exams, you should also ask each student how many days absence they have had so far this year

The results will be plotted on a graph

One measure of the functioning of the immune system is the level of activity of white blood cells. What does the graph below tell you about the relationship between stress and the level of activity of white blood cells? (2 marks)