Contingency Table
Perpetual set study using the Leeper Lady stimulus
E values are calculated by multiplying marginal totals and then dividing by the grand total.
Cell 1 33x68/86 = 26.09
Cell 2 33x18/86 = 6.9
Cell 3 68x53/86 = 41.9
Cell 4 18x53/86 = 11.09
Chi-squared formula X = (0-E) /E for each cell.
Cell 1 (32-26.09) /26.09 = 1.3
Cell 2 (1-6.9) /6.9 = 5.0
Cell 3 (36-41.9) /41.9 = 0.8
Cell 4 (17-11.09) /11.09 = 3.1
Summation of Chi-Squared = 10.2
Degrees of freedom are calculated by taking (row1) from (column 1)
(2-1) (2-1)
1x1 = 1 Degree of freedom
Calculated value = 10.2, DF = 3.84
Therefore the results are significant and the hypothesis is accepted whereas the null hypothesis is rejected.
AIM : The aim of my study of the “Leeper Lady” is to look for age differences in perception of the stimulus in which there is both a young and an old face only one of which can bee seen at one time.
Hypothesis : The hypothesis of this study is that there will be a different in perception of the ambiguous stimulus depending on the age of the participants.
Null hypothesis : The null hypothesis is that there will be no significant difference and any difference will be to do with chance or some other factor.
D.V. (Dependant variable) : The dependant variable is the measured number of participants both old and young, who fell into the different categories.
I.V. (Independent Variable) This is the study of the ages of the participants.
Method
The study used was a lab experiment.
Design : The design used was of independent measures as both young and old people were used for the study.
Participants : In total 86 participants were used these included 53 older people and 33 young people. All participants where from a foundation study of variable ages.
Materials : A picture of the Leeper ambiguous lady was used in the study, a contingency table to show the data recorded, a calculator to work out the chi-squared formula and a statistical table so the critical values for 1 degree of freedom could be found.
Procedure : The procedure I use was to ask each participant to observe the stimulus and ask them what did they see, if they seen a face I asked them what age did the face appear to be, as both faces could not be seen at one time. Each result was then recorded and a chi-squared formula was then used to find the expected values. I then thank each participant for taking part in the study.
Results
The nominal data for 86 participants was analysed using the non-parametric chi-squared test where the chi-squared formula was 10.2 and the critical value=DF1 was 3.84 this told me the results were significant and then the hypothesis was accepted and the null hypothesis was rejected. In the study there was an overall age difference in the perception of the Leeper Lady stimulus.
Discussion
In the study of the Leeper Lady stimulus I found that the chi-squared formula was 10.2 whereas the critical value for DF1 was that of 3.84, with these findings I was able to establish that the hypothesis was accepted and the null hypothesis was rejected. The results from this told me that the Leeper Lady theory worked as the younger participants observed the young face and the older participants observed the old face.
Shortcomings : The shortcomings could be different as the gender may have been unequal, and men maybe would have seen the young face rather than the old face. There also may have been a large age difference in the participants, or maybe very few participants took part in the study.
Improvements : If I was to repeat the study I would like to try a different stimulus to see if the results were significant. The ages of the participants could be more varied or of the same age. Using the stimulus on people who work with the elderly and others who work with children could be of an interesting outcome.
Name : Liz Dalzell
Subject : Psychology
Assignment : The Leeper Lady Study
Tutor : Marietta
