Question

Download data.beergoggles.csv. The hypothesis is that after alcohol had been consumed, subjective perceptions of physical attractiveness would become more inaccurate (beer-goggles effect). There were 48 participants: 24 males, 24 females. The researcher took 3 groups of 8 participants to a night club. One group got no alcohol, one group 2 pints, and one group 4 pints. At the end of the evening the researcher took a photograph of the person the participant was chatting up. The attractiveness of the person on the photo was then rated (0 - 100) by independent judges. Use a 0.03 significance level and apply the methods of two-way analysis of variance. Was there an interaction between the two factors? What is your conclusion?

Female	None	65
Female	None	70
Female	None	60
Female	None	60
Female	None	60
Female	None	55
Female	None	60
Female	None	55
Female	2 Pints	70
Female	2 Pints	65
Female	2 Pints	60
Female	2 Pints	70
Female	2 Pints	65
Female	2 Pints	60
Female	2 Pints	60
Female	2 Pints	50
Female	4 Pints	55
Female	4 Pints	65
Female	4 Pints	70
Female	4 Pints	55
Female	4 Pints	55
Female	4 Pints	60
Female	4 Pints	50
Female	4 Pints	50
Male	None	50
Male	None	55
Male	None	80
Male	None	65
Male	None	70
Male	None	75
Male	None	75
Male	None	65
Male	2 Pints	45
Male	2 Pints	60
Male	2 Pints	85
Male	2 Pints	65
Male	2 Pints	70
Male	2 Pints	70
Male	2 Pints	80
Male	2 Pints	60
Male	4 Pints	30
Male	4 Pints	30
Male	4 Pints	30
Male	4 Pints	55
Male	4 Pints	35
Male	4 Pints	20
Male	4 Pints	45
Male	4 Pints	40

Answer 1

We can apply the Rcode to obtain the anova table.

Here is the R code

data=read.csv("data.beergoggles.csv",head=T)

attach(data)

summary(aov(ratings~sex*alcohol))

Here is the anova table:-

Df Sum Sq Mean Sq F value Pr(>F)   
sex 1 169 168.8 2.032 0.161   
alcohol 2 3332 1666.1 20.065 7.65e-07 ***
sex:alcohol 2 1978 989.1 11.911 7.99e-05 ***
Residuals 42 3488 83.0
---
Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1

As the p-value for the interaction affect between sex and alcohol (7.99e-05) is very less than 0.03, we shall say that there is an interaction affect between sex and alcohol. Also there is a significant effect due to alcohol because the corresponding p-value= 7.65e-07 is also very small.

Thus the conclusion is that hypothesis is true that after alcohol had been consumed, subjective perceptions of physical attractiveness would become more inaccurate and also that beergogle effect varies with gender.