Stats Survey Data – t-Tests
North Georgia Mathematics (Fall 2013 Data)
Directions: Complete the correct t-procedure for each set of observed data below.
1. Whose Relationship Beliefs are more Toxic? A recent survey measured
naïve relationships beliefs in a college population. The TXREL sample data
for males and females is given below. Test for a significant difference at
the .01 level.
2. Do younger students sleep more? A recent survey measured
the amount of sleep (two-night total) in a college population
with two groups, one who were 21 years old or older, the
other who were not yet 21 years old. Do the younger students
sleep significantly more than the older students? Test at the
.05 level of significance.
Females
AVG 26.65
SD 5.32
N
100
Males
30.11
6.17
63
21 or older 20 or younger
AVG
13.52
14.28
SD
2.54
2.87
N
50
113
3. Estimate with a 90% level of confidence the mean GPA for the following 21-year-old female North
Georgia students.
3.7 2.8 3.26 3.3 3.3 3.6 2.13 2.23
3.36 3.0 3.2 3.14 3.7 2.58 3.26
4. Estimate with a 95% level of confidence the mean Anxiety for the following 20-year-old males North
Georgia students.
26 29 27
24 22 35
27
20
28
29
16
22 26 23
24 20 19
27
29
19
23
27
5. The population Perfectionism scores for North
93 81 65 100 81 67 94 85 81
Georgia students has been esatblished: the
67 73 80 78 116 60 76 81 133
distribution is N(82,18). The scores below are
from the sophomores at North Georgia. Test at the .05 level whether sophomores have higher levels
of perfectionism than the general population.
6. Do younger males use more aggressive humor? The data
below is from 20-year-old males whose aggressive humor
was measured (HSQ). The population has the N(24, 5.2)
distribution for aggressive humor. Test at the .01 level.
26 26 29 26 27 23 26 29
23 24 27 26 24 25 25 24
7. Are young females more playful? The data
130 141 150 167 157 161 145 154 143
below is from 20-year-old females whose
133 145 153 144 153 140 155 148
playfulness was measured in a recent
survey. The overall population has the N(136,20) distribution for playfulness. Test at the .01 level.
8. Do females text less than males? A recent survey measured the amount
of “inappropriate” texting for males and females at North Georgia. Test
at the .05 level.
9. Do older students (21+) use less self-enhancing humor? The
population has the N(28,5) distribution for Self-Enhancing
Humor. Test at the .05 level.
Females Males
AVG
8.67
10.07
SD
3.87
4.40
N
90
57
24 26 27 26 20 33 35 32
32 28 27 22 24 30 16 32
Solutions
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9.
Ha : µF ≠ µM, ind. samples t-test, t= -3.67, p=0.00036, Reject H0
Ha : µy > µo, ind. samples t-test, t= 1.69, p=.0469, Reject H0
T-interval: Between 2.88 and 3.32, margin of error = .22
T-interval: Fails verification, outlier (X = 35). Do not proceed – data not appropriate for t-procedures.
Fails verification, outlier (X = 133). Do not proceed – data not appropriate for t-procedures.
Ha : µ > 24 , t = 3.57 , p = .0014 , Reject H0
Ha : µ > 136 , t = 5.24 , p = .000041 , Reject H0
Ha : µf < µm, ind. samples t-test, t= -1.97, p=.0258 Reject H0
Ha : µ < 28 , t = -.678 , p = .2541 , Fail to reject H0