reading level, and the third received one written at the tenth-grade read-
ing level. After booklets were received, all subjects were administered a
second test. The mean score di¤erences (postscoreprescore) are given
in Table E7.20 along with their standard deviations and sample sizes.
Test to compare the three groups simultaneously. Name your test and
state clearly your null and alternative hypotheses and choice of test size.TABLE E7.20
No Booklet 5th-Grade Level 10th-Grade Level
x 0.25 1.57 0.63
s 2.28 2.54 2.38
n 44 44 417.21 A study was conducted to investigate the risk factors for peripheral
arterial disease among persons 55 to 74 years of age. Table E7.21 pro-
vides data on LDL cholesterol levels (mmol/L) from four di¤erent sub-
groups of subjects. Test to compare the three groups simultaneously.
Name your test and state clearly your null and alternative hypotheses
and choice of test size.
TABLE E7.21
Group n xs- Patients with intermittent clau-
dication
73 6.22 1.62- Major asymptotic disease cases 105 5.81 1.43
- Minor asymptotic disease cases 240 5.77 1.24
- Those with no disease 1080 5.47 1.31
7.22 A study was undertaken to clarify the relationship between heart disease
and occupational carbon disulfide exposure along with another impor-
tant factor, elevated diastolic blood pressure (DBP), in a data set ob-
tained from a 10-year prospective follow-up of two cohorts of over
340 male industrial workers in Finland. Carbon disulfide is an indus-
trial solvent that is used all over the world in the production of viscose
rayon fibers. Table E7.22 gives the mean and standard deviation (SD)
of serum cholesterol (mg/100 mL) among exposed and nonexposed
cohorts, by diastolic blood pressure (DBP). Test to compare simulta-
neously, separately for the exposed and nonexposed groups, the mean
serum cholesterol levels at the three DBP levels using one-way ANOVA.
Also, compare serum cholesterol levels between exposed and nonexposed
cohorts at each level of DBP by using two-samplettests. Draw your
conclusions.
EXERCISES 279