PART I (22 points)
A study by Chen and colleagues (2014) tested what is known as the ‘beer-goggles effect.’ This is the idea that subjective perceptions of physical attractiveness becomes less accurate after drinking alcohol. The logic is that: (i) alcohol consumption reduces accuracy in symmetry judgements, and (ii) symmetrical faces (like Denzel Washington) are rated as more attractive. Thus, drinking alcohol will lead people to rate unattractive people as being more attractive than they actually are (based on facial symmetry) – the ‘beer-goggles effect.’ However, drinking alcohol should not impact attractiveness ratings for people who are initially highly attractive (based on facial symmetry). The data below is not the actual data from the Chen et al. (2014) study.
There are 32 participants who were randomly assigned to one of three Alcohol Conditions:
(i) A Low-dose group who drank 500ml of low-strength beer (n = 16)
(ii) A High-dose group who drank 500ml of high-strength beer (n = 16)
After their drink, participants rated the attractiveness of 50 faces that had been pre-assigned (based on symmetry) to one of two Face Types: Attractive or Unattractive. Thus, half of the participants within a group (n = 8) received 50 attractive faces and the other half (n = 8) received 50 unattractive faces.
The attractiveness of the faces was rated on a 0 to 10 point scale (higher numbers = more attractive) and averaged together for each participant. This Attractiveness Rating is the dependent variable.
Round all calculations to 2 decimal points as you conduct them. This will help to ensure that round-off error is the same for everyone (including for the grading TAs).
Use this scenario to answer the questions in Part 1.
Alcohol Condition
Face Type Low-dose Group
n = 16 High-dose Group
n = 16
Attractive
n = 16 M = 6.63
SD = 0.74 M = 6.75
SD = 1.28
Unattractive
n = 16 M = 4.25
SD = 1.39 M = 6.50
SD = 1.69
ANSWER
ANSWER
a. Calculate the two means that should be compared to consider whether there is a possible main effect for Alcohol Condition? [Hint. The means are not in the table. Show your calculations.] (1 points)
ANSWER
b. Calculate the two means that should be compared to consider whether there is a possible main effect for Face Type? [Hint. The means are not in the table. Show your calculations.] (1 points)
ANSWER
c. Which means should be compared to consider whether there is a possible interaction between Alcohol Condition and Face Type? (1 points)
ANSWER
a. Compute your MSwithin and MSbetween. (2 points)
ANSWER
b. Convert MSbetween to SSbetween. (1 points)
ANSWER
c. Compute the MSalcohol and SSalcohol. (2 points)
ANSWER
d. Compute the MSface and SSface. (2 points)
ANSWER
e. Compute the SSIXN. (1 point)
ANSWER
f. Compute the MSIXN. (1 point)
ANSWER
g. First, restate your MSwithin, MSalcohol, MSface, and MSIXN from the previous questions. Then compute your F-ratios. You MUST show your work for the F-ratio calculations. (3 points)
ANSWER
h. Correctly fill in the ANOVA Table. The values given to you below are so you can check your work, so if your values are slightly different due to rounding error, change the values below to what you calculated. If your values are very different, recheck your calculations. (1 point)
Source SS df MS F-ratio
Between Groups
Alcohol Condition
Face Type Condition
Alcohol x Face Type 5.15
Within Groups
Total 82.80 31
ANSWER
PART II
For Part II of the Assignment this week you will actually be reporting on the analyses that you conducted in lab section, rather than conducting a new set of analyses. Thus, you will not be copy and pasting R code below. Instead, you will focus on interpreting the output.
ANSWER
ANSWER
ANSWER
a. Paste the R code below. (1 point)
ANSWER
b. Paste the line graph below. (1 point)
ANSWER
Sample Solution