A researcher wants to know if drinking beer makes a person more attractive to mosquitos. 120 people were recruited to partake in this experiment. Each person was randomly assigned to either drink beer or to ingest water. The subject after drinking their beverage was seated close enough so that odor from the individual would be detectable by the mosquitoes (note that the mosquitoes could not actually touch the humans). The researcher then recorded whether or not the mosquito flew toward the subject (assumed flying toward person meant they were attracted to them). 68 people were assigned to drinking beer, while the other 52 were assigned to drinking water. Out of the 68 who drank beer 43 of them had a mosquito fly toward them, while 26 of those who drank water had a mosquito fly toward them. (This is based loosely off an experiment performed by Lefevre et al. (PLOS ONE, 2010)). Research Question: Are mosquitos more attracted to people who drink beer than water?
1. Identify the explanatory and response variables. State their type.
2. Fill out the 2x2 table below.
TOTAL TOTAL
3. State the parameter of interest and assign a symbol.
4. Calculate the conditional proportions. What does each stand for? Assign a symbol to each.
5. Are the values in question #4 statistics or parameters? Explain.