Stat 240 Dec. 10 Lab Key
Activity 1:
a. H0: 1 = 2 =3
b. p–value = 0.000, reject the null hypothesis.
F-value = 9.57
The p-value is the probability an F-statistic could be larger than 9.57
c. Means are
Front 0.360
Middle 0.750
Back 1.417
d. The interval for Back does not overlap with the other two indicating a difference. The other two
intervals only slightly overlap indicating a probably difference.
e. The output is:
Intervals for (column level mean) - (row level mean)
Front
Middle
Back
0.581
1.533
Front
0.242
1.091
-0.750
-0.031
Intervals for differences in means are
Back – Front:
0.581 to 1.5333
Back – Middle: 0.242 to 1.091
Front – Middle: -0.750 to -0.031
f. Each interval excludes 0, so in each event we can say there is a difference.
Activity 2:
a. Both variables are categorical so the correct analysis is chi-square (see chapter 6)
b. Null: No relationship between gender and finger length pattern
Alternative: There is a relationship
c. chi-square = 10.719, p-value =0.005; conclude there is a relationship
d. females more likely to say their index finger is longest, males more likely to say ring finger
g. Finger length pattern is probably same for all adults so population may be “all adults.” The first
activity was specific to being in college so population = college students.
Activity 3:
A. Histogram has two peaks corresponding to differing answers by females and males.
B. Output is
Variable
IdealHt
Sex
Female
Male
Variable
IdealHt
Sex
Female
Male
N
157
59
Mean
66.519
72.576
SE Mean
0.161
0.324
Median
66.000
72.000
Minimum
60.000
67.000
TrMean
66.482
72.547
Maximum
73.000
81.000
Q1
65.000
71.000
StDev
2.011
2.486
Q3
68.000
74.000
5-number summary for females is 60, 65, 66, 68, 73. For males: 67, 71, 72, 74, 81.
C. About one-fourth of the females would like to be taller than 68 inches (and about 3/4 would like to be
shorter).
D. About one-half of the males would like to be taller than 72 (and on-half would like to be shorter).
E. For females it seems roughly symmetric (look at distances from median to extremes and from
quartiles to extremes). Males might be less symmetric although the “81” could be an outlier.