A psychologist employs a two-factor experiment to study the combined effect of s
ID: 3201626 • Letter: A
Question
A psychologist employs a two-factor experiment to study the combined effect of sleep deprivation and alcohol consumption on the performance of automobile drivers. Before the driving test, the subjects go without sleep for various time periods and then drink a glass of orange juice laced with controlled amounts of vodka. Their performance is measured by the number of errors made on a driving simulator. Two subjects are randomly assigned to each cell, that is, each possible combination of sleep deprivation (either 0, 24, 48, or 72 hours) and alcohol consumption (either 0, 1, 2, or 3 ounces), yielding the following results:
NUMBER OF DRIVING ERRORS
ALCOHOL CONSUMPTION (OUNCES) SLEEP DEPRIVATION (HOURS)
0 24 48 72 row T2row
0
3
2
4
5
4
5
6
1
3
3
3
6
7
5
8
3
5
2
5
8
11
7
12
4
6
4
7
10
13
9
15
EX =1466 Tcolumn
T2column
25
625
30
900
64
4096
67
4489
G = 186
G2= 34596
0
0
3
2
4
5
4
5
6
29 841 11
3
3
3
6
7
5
8
36 1296 23
5
2
5
8
11
7
12
53 2809 34
6
4
7
10
13
9
15
68 4624EX =1466 Tcolumn
T2column
25
625
30
900
64
4096
67
4489
G = 186
G2= 34596
Explanation / Answer
2-Way ANOVA is applied.
Here there are 2 factors with 4 levels in each factor. There are 2 replications in each experiment.
Using MS Excel 'data analysis' add-in, we get result:
By looking at p-values for each factor and interaction, we conclude that:
Both the factors 1 &2 have impact on driving errors whereas their interaction doesn't have any impact. (at 5% level)
ANOVA Source of Variation SS df MS F P-value F crit Factor-2: ALCOHOL CONSUMPTION (OUNCES) 115.125 3 38.375 9.164179 0.000918 3.238872 Factor-1: SLEEP DEPRIVATION (HOURS) 182.625 3 60.875 14.53731 7.84E-05 3.238872 Interaction 20.125 9 2.236111 0.533997 0.829228 2.537667 Within 67 16 4.1875 Total 384.875 31Related Questions
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