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Pearson Correlation
Fred believes that students can be categorized as excellent, good, mediocre, bad and
extremely bad, and that these categories hold true across all subjects. That is,
excellent students do exceptional work in all subjects, good students do well in all
subjects, etc. To test this hypothesis, he examines the records of 120 students to
determine their GPA in five types of courses; math (mathgpa), English (enggpa), history
(histgpa), science (sciengpa), and social sciences (socgpa). The data are organized
with 5 variables (GPA in each type of course) and 120 cases.
Independent t-test
Billie wishes to test the hypothesis that overweight individuals tend to eat faster
than normal weight individuals. To test this hypothesis, she classifies individuals
who visit McDonalds restaurant and order the Big Mac special as overweight, normal
weight, or neither overweight nor normal weight. The latter group is not used.
She records the time it takes for the normal and overweight individuals to consume
the meal. Forty persons are characterized and recorded, 10 overweight and 30 normal
weight. The data file is organized with 2 variables (grouping variable with two
levels 1=overweight and 2=normal weight)(time to consume meal in seconds) and 40
cases.
Paired Samples Statistics / ANOVA
The number of pimples and blackheads on five subjects' faces were counted at stage one
(baseline: A=15, B=12, C=3, D=5, & E=16) of the study. Subjects were then introduced to a
special diet (no controls were used). During the mid-stage the number of pimples and blackheads
was conted again A=12, B=10, C=1, D=3, & E=15). The last count was taken during the final stage
(A=8, B=5, C=0, D=0, & E=10). Is the special diet making a difference for these subjects?
Chi-Square
Kristen is interested in evaluating whether the method of cooking potato chips affects
the taste of the chips. She has 48 individuals volunteer to participate in her potato
chip study. Each subject tastes chips cooked using three different methods; fried in
animal fat (chip=1), fried in canola oil (chip=2), and baked (chip=3). Subjects are
instructed to indicate which chip they prefer. Kristen hypothesizes that subjects will
prefer chips fried in canola oil over the other two. Seven subjects prefer chip 1, 33
prefer chip 2, and 8 prefer chip 3. The data file has one variable (chip preference)
and 48 cases.
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