MPH501 Module 4 Quiz Latest 2020 January

MPH501 Quantitative Methods for Public Health Application

Module 4 Quiz

Question 1 The following table displays descriptive statistics on the participants involved in a study.

Generate a 95% confidence interval for the mean age among participants assigned to the placebo.

Generate a 95% confidence interval for the difference in mean ages in participants assigned to the experimental versus the placebo groups.

Generate a 95% confidence interval for the difference in mean body mass index in participants assigned to the experimental versus the placebo groups.

Question 2 A clinical trial is run to assess the efficacy of a new pacemaker device in patients with atrial fibrillation (AF).  Two hundred participants are randomized to receive the new pacemaker or a currently available pacemaker.  There are two primary outcomes of interest – the number of days in a three-month period with an atrial fibrillation event and hospitalization for atrial fibrillation over the three month follow-up period.  Data on baseline characteristics and the outcomes are shown below.

Compute a 95% confidence interval for the difference in mean number of days with an AF event between participants receiving the new pacemaker as compared to the available pacemaker.

Compute a 95% confidence interval for the mean number of days with an AF event among participants receiving the new pacemaker.

Question 3 The following table shows the numbers of patients classified as underweight, normal weight, overweight and obese according to their diabetes status.

If a patient is selected at random,

What is the probability that they are overweight?                            

What is the probability that they are obese and diabetic?                

What proportion of the diabetics are obese?                                    

What proportion of normal weight patients are not diabetic?          

What proportion of patients are normal weight or underweight?   

Question 4 An investigator wants to test whether exposure to second-hand smoke before 1 year of life is associated with development of childhood asthma (defined as asthma diagnosed before 5 years of age).  Give two possible study designs and indicate the pros and cons of each.  Then, provide your recommendation for the most efficient design.

Question 5 A study is run to estimate the incidence of atrial fibrillation (AF) in men and women over the age of 60.  Development of atrial fibrillation was monitored over a 10 year follow-up period.  The data are summarized below.

Compute the cumulative incidence of AF in men and in women

Compute the relative risk of AF incidence comparing men to women

Compute the odds ratio of AF incidence comparing men and women

Question 6 The following data were collected in a survey of 8th graders and summarize their cell phone status.

What proportion of the 8th graders have cell phones?

What proportion of the boys do not have cell phones?

Is  ownership of a cell phone independent of sex?  Justify your answer.

What proportion of smart phone users are boys? 

Question 7 The following table shows the results of a screening test hypothesized to detect persons at risk for side effects of a new cosmetic surgery.

Compute the sensitivity of the test 

Compute the specificity of the test

Compute the false positive fraction

Compute the false negative fraction

Question 8 A random sample of eight adults aged 30 years were asked how much they spent on medical costs in the year 2009.  The following data were measured.

300      140      5600    520      470      700      640      1200

Compute the sample mean

Compute the sample standard deviation

Compute the sample median

Compute the first and third quartiles

Question 9 Four hundred melanoma patients were diagnosed according to the type of skin cancer and the location of the skin cancer.  This data is presented below.

 What proportion of patients had Superficial Spreading Melanoma? 

Of patients with a skin cancer on the Trunk, what proportion had a nodular skin cancer?

What proportion of patients had a Hutchinson’s Melanomic Freckle on the extremities?

 Is type of skin cancer independent of location?  Justify your answer.

Question 10The gestation period for human births can be taken as normally distributed with a mean of 266 days and a standard deviation of 16 days.

What is the probability that a randomly chosen baby had a gestation period of more than 280 days?

If a gestation period if 276 days, what percentile among human births is this?