Blog

Find the greatest common divisor of 12 and 30. 

What percentage of red blood cells with glucose-coated hemoglobin does the A1C test measure? 

The pancreas secretes insulin from clusters of cells called: 

In the UpWork Case Study, what is the “recommended flag” based on?

A home health nurse cares for a patient diagnosed with a complete thoracic 5 (T5) spinal cord injury after falling from a ladder. The nurse assesses the patient and develops a nursing diagnosis of “Situational low self-esteem related to sudden decrease in independence.” Which nursing intervention should be included in the patient’s plan of care?

Please read the two sentences below: To conclude, there was an association between physical activity and blood pressure in this study. We aimed to examine loneliness as a risk factor for depression.   Which of the two sentences above contain nominalizations?

Suppose a team of researchers investigated the effect of drinking caffeinated beverages (i.e., yes versus no) on migraines among American women aged 18-40. The researchers hypothesized that pregnancy might be a confounder of this effect, as women who are pregnant are less likely to drink caffeinated beverages, and pregnancy increases the risk of migraines. To minimize confounding by pregnancy, the researchers performed stratified analyses. The results from these stratified analyses are reported in Table 1.   Table 1. Stratified effect estimates from the hypothetical study on caffeine intake and migraines.   Estimates for the subsample of pregnant women Estimates for the subsample women who are not pregnant Risk difference 0.05 0.05 Risk ratio 1.50 2.00   The researchers would like to recombine the stratified effect estimates reported in Table 1 using Mantel-Haenszel methods. Is it appropriate to apply the Mantel-Haenszel method to recombine the stratum-specific estimates of the risk differences (yes/no)? (1 point) Describe why it is/is not appropriate to apply the Mantel-Haenszel method (max. 2 points). Is it appropriate to apply the Mantel-Haenszel method to recombine the stratum-specific estimates of the risk ratios (yes/no)? (1 point) Describe why it is/is not appropriate to apply the Mantel-Haenszel method (max. 2 points).

Suppose a team of researchers investigated the association between obesity and gallstones using a prospective cohort study design. The researchers were concerned about confounding by high cholesterol diet, so they performed a few different analyses in which they attempted to minimize confounding. The results of their analyses are reported in Table 1.   Table 1. Unadjusted, stratified, and Mantel-Haenszel effect estimates from the hypothetical study on obesity and gallstones.   Unadjusted Estimates Estimates for the subsample with a low cholesterol diet Estimates for the subsample with a high cholesterol diet Mantel-Haenszel estimates Odds ratio 3.24 3.01 2.83 2.92 Risk difference 0.20 0.16 0.17 0.17   Based on the information in Table 1 report the following information: Is it appropriate to estimate a odds ratio using Mantel-Haenszel methods (yes/no)? (2 points) Explain why this is/is not appropriate (2 points). Is it appropriate to estimate a risk difference using Mantel-Haenszel methods (yes/no)? (2 points) Explain why this is/is not appropriate (2 points).

Suppose a team of researchers is interested in investigating the effect of physical activity on atherosclerosis. Before conducting their study, they drew a directed acyclic graph (DAG) to determine what confounder variables they need to adjust for in the analyses. Figure 1 shows the DAG that the researchers drew.   For each of the variables in Figure 1 (stroke, LDL cholesterol, and socioeconomic status) describe 1) what type of “third variable” each variable is (1 point), 2) whether the researchers should or should not adjust for the respective variable in the analysis stage to minimize confounding (1 point), and 3) why the researchers should or should not adjust for the respective variable (1 point).  

This class is a full term class.