Logistic Regression: A Self-learning Text, Third Edition (Statistics in the Health Sciences)

Test True or False (Circle T or F)

T F 1. The disease categories absent, mild, moderate,

and severe can be ordinal.

T F 2. In an ordinal logistic regression (using a propor-

tional odds model) in which the outcome vari-

able has five levels, there will be four intercepts.

T F 3. In an ordinal logistic regression in which the out-

come variable has five levels, each independent

variable will have four estimated coefficients.

T F 4. If the outcome Dhas seven levels (coded 1,

2,..., 7), then P(D4)/P(D<4) is an example

of an odds.

T F 5. If the outcomeDhas seven levels (coded 1, 2,

..., 7), an assumption of the proportional odds

model is that P(D3)/P(D<3) is assumed

equal to P(D5)/P(D<5).

T F 6. If the outcomeDhas seven levels (coded 1, 2,

..., 7) and an exposureEhas two levels (coded

0 and 1), then an assumption of the propor-

tional odds model is that [P(D3|E¼1)/

P(D<3|E¼1)]/[P(D3|E¼0)/P(D<3|E¼0)]

is assumed equal to [P(D5|E¼1)/P(D<5|

E¼1)]/[P(D5|E¼0)/P(D<5|E¼0)].

T F 7. If the outcome Dhas four categories coded

D¼0, 1, 2, 3, then the log odds ofD2is

greater than the log odds ofD1.

T F 8. Suppose a four level outcomeDcodedD¼0, 1,

2, 3 is recodedD*¼1, 2, 7, 29, then the choice

of usingDorD*as the outcome in a propor-

tional odds model has no effect on the parame-

ter estimates as long as the order in the

outcome is preserved.

9. Suppose the following proportional odds model is
   specified assessing the effects of AGE (continuous),
   GENDER (female¼0, male¼1), SMOKE (non-
   smoker¼0, smoker¼1), and hypertension status
   (HPT) (no¼0, yes¼1) on four progressive stages of
   disease (D¼0 for absent,D¼1 for mild,D¼2 for
   severe, andD¼3 for critical).

ln

PðDgjXÞ

PðD<gjXÞ

¼agþb 1 AGEþb 2 GENDER

þb 3 SMOKEþb 4 HPT;

whereg¼1, 2, 3.

Use the model to obtain an expression for the odds of

a severe or critical outcome (D 2) for a 40-year-old

male smoker without hypertension.

Test 487