Question

Question 2. [9 marks total] Human papillomavirus (HPV) is a very common STI that most sexually
active persons will encounter during their lifetimes. While many people clear
the virus, certain strands can lead to adverse health outcomes such as
genital warts and cervical cancer.

Suppose that you selected a random sample from a population and collected
these data on age and HPV status for the sample:

|Age Group| HPV + | HPV - | Row total |
|:-------------:|:-------------------|:-----------------:|:-----------:|
|14-19 | 160 | 492 | 652 (33.9%) |
|20-24 | 85 | 104 | 189 (9.8%) |
|25-29 | 48 | 126 | 174 (9.1%) |
|30-39 | 90 | 238 | 328 (17.1%) |
|40-49 | 82 | 242 | 324 (16.9%) |
|50-59 | 50 | 204 | 254 (13.2%) |
| Col total | 515 (26.8%) | 1406 (73.2%) | 1921 |

2.a) [1 mark] Which variable is explanatory and which is response?

Answer 1

By the definition we know that a variable is called EXPLANATORY VARIABLE if the variable is not affected by any other variable i.e. independent but not for a certain. And a variable is called RESPONSE VARIABLE if the variable depends on other variable or variables.

Here in this case the EXPLANATORY VARIABLE is AGE GROUP because this is independent but not for a certain and does not depend on other variables. But on another hand HPV+, HPV- and ROW TOTAL depend on the various age groups as the sexually activeness is mainly depends on the age. So these variables are RESPONSE VARIABLE.