Reflection on Biostatistics Topic 4

Before you attempt the exercise, please read the remainder of Chapter 5 in the e-book.

In topic 3, we learned how to test hypotheses about population means. In this topic, we will look at count data. Read on for the exercise questions…

Exercise: Results for travel to a high-burden TB country.

In this study, 300 children received a tuberculin skin test (TST), of which 80 had a positive TST result. [Note: parents of all included children consented to be in this study.] 

Of the 300 children, we know 22 had travelled to a high-burden TB country during the 12 months prior to their TST.

We also know 12 of the 80 children with a positive TST had travelled to a high-burden TB country during the 12 months before their skin test.

Q1: Populate this table using the information provided above

Once you have done this:

Q2: Formulate a hypothesis for this question

Q3: Choose an appropriate test statistic to test the association and justify the use of the statistic

Q4: Calculate an odds ratio (OR) and provide an interpretation of the findings.

Q5: Calculate a relative risk ratio (RR) and provide an interpretation of the findings.

You can use any statistical package available to you if needed!