Mont Blanc is the highest mountain in western Europe at 4,810 m, or 15,781 feet. The climb to reach the summit is not that technical so thousands attempt it each year. However, many of these climbers die because they are not physically prepared for the altitude and effort. There is concern that some take certain medications to try to make up for their unpreparedness. Some diuretics are used to help with altitude sickness, but their side effects can be detrimental to someone attempting this climb. Researchers Robach et al. (2016) used a device to blindly take urine samples from urinals that are used by climbers heading to the summit. They found that 81 of 357 samples contained a diuretic. Although certainly not a random sample, we will assume this sample is representative of all the male climbers headed to the summit. 

a. Describe the parameter, π, that the researchers are trying to estimate. 

b. Use the One Proportion applet, repeatedly testing possible values for π, to construct a 95% confidence interval for π to 2 decimal places.