MPH516 Module 5 Quiz Latest 2021 August

MPH516 Epidemiology and Biostatistics for Public Health Application 2

Module 5 Quiz

Question 1A researcher was interested in predicting whether a person would attempt to commit suicide (score = 1) or not (score = 0) from their depression scores. They found that the value of exp b was 2.56. How should this value be interpreted?

If two people have depression scores that differ by 1 unit, then the odds of the person with the higher score attempting suicide are 2.56 higher than for the other person.

2.56 times more people who attempted suicide scored highly on depression.

If two people have depression scores that differ by 1 unit, then the odds of the person with the higher score attempting suicide are 2.56 lower than for the other person.

Suicide rates are 2.56 times as high in depressed people.

Question 2Asbestos exposure has been associated with:

pesticides from the organochloride family.

asbestosis, malignant mesothelioma, and lung cancer.

metallic compounds.

vinyl chloride.

Question 3A sentinel health event refers to:

the correlation between daily mortality and increased air pollution.

the nuclear plant accident in Chernobyl, Ukraine.

a case of unnecessary workplace disease that serves as a warning signal.

None of these is correct.

Question 4A situation in which the combined effect of several exposures is greater than the sum of the individual effects is:

threshold.

latency.

synergism.

None of these is correct.

Question 5Exposure to electric and magnetic fields has been linked to:

childhood leukemia risk.

lung cancer.

central nervous system damage.

All are correct.

Question 6In logistic regression, the dependent variable is called a logit, which is

The natural log of the odds

The rolling mean

A log rolling

A mean log

Question 7It has been suggested that occupational exposure to benzene in the petroleum industry increases the risk of developing leukemia. The levels of benzene to which workers in this industry have been exposed were high from 1940 to 1970, but since 1970 have been significantly reduced. What kind of study design, using petroleum workers, would provide the most useful information on whether benzene affects incidence rates of leukemia in this industry? (You may assume that records of individual worker assignments to jobs involving benzene exposure have been maintained by the industry.)

Experimental

Retrospective cohort

Prospective cohort

Case-control

Cross-sectional

Question 8Large log-likelihood values do not show

The extent of the relationship between independent and dependent variables.

That there are a large number of unexplained observations in the data.

That there is a large measure of deviance.

That the model is a good fit.

Question 9Logistic regression is used when you want to

Predict a continuous variable from dichotomous ones.

Predict a dichotomous variable from continuous or dichotomous variables.

Predict any categorical variable from other categorical variables.

Predict a continuous variable from dichotomous or continuous variables.

Question 10Logistic regression

Estimates values in the outcome variable.

Estimates a probability that the outcome variable assumes a certain value.

Estimates probabilities in the outcome variable.

Estimates the probability that the predictor variables assume certain values.

Question 11One must use care in interpreting occupational differences in morbidity and mortality because:

good health status may be a factor for selection into a job.

occupations involving physical activity tend to cause heart attacks among older workers.

occupational stress, even in extreme situations, is difficult to quantify.

good health status may be a factor for selection into a job, occupations involving physical activity tend to cause heart attacks among older workers, and occupational stress, even in extreme situations, is difficult to quantify.

Question 12The healthy worker effect refers to the observation that:

exercise on the job causes workers to become healthy and gain years of life.

healthy persons are more likely to gain employment than unhealthy persons.

unemployed persons tend to have lower mortality than employed persons.

All are correct.

Question 13The lowest dose at which a particular response may occur is:

threshold.

latency.

synergism.

None of these is correct.

Question 14The odds of an event are

The ratio of the probability of an event not happening to the probability of the event happening.

The ratio of the probability of an event happening to the probability of the event not happening.

The probability of an event occurring.

None of the above.

 Question 15The time period between initial exposure and a measurable response is:

threshold.

latency.

synergism.

None of these is correct.

Question 16What does logistic regression not do?

Predict a dependent variable on the basis of several independent variables.

Determine the variance in the dependent variable explained by the independent variables.

Rank the relative importance of independent variables.

Assess the impact of covariate control variables.

Question 17What is an alternative to logistic regression when the dependent variable has more than two classes?

Binomial regression

Logit regression

Legit regression

Multinomial regression

Question 18What is suggested by very high standard errors in parameter estimates in logistic regression?

Shrinkage

Multicollinearity

An outlier

A dummy variable

Question 19Which of the following statements is not true about the Wald statistic?

The Wald statistic assesses the individual contribution of a predictor to a logistic regression model.

The Wald statistic tends to be biased when the regression coefficient is large.

If the Wald statistic is equivalent to the t-statistic in multiple regression.

The Wald statistic has a t-distribution.

Question 20Which of the following is not a research question which could be investigated with logistic regression?

Prediction of group membership

Strength of association between criterion and predictors

Differences between groups

Interaction between predictors