A recent study examined hearing loss data for 1,771 U. S. teenagers. In this sample, 333 were found to have some level of hearing loss. News of this study spread quickly, with many news articles blaming the prevalence of hearing loss on the higher use of ear buds by teens. At MSNBC. com (8/17/2010), Carla Johnson summarized the study with the headline: "1 in 5 U. S. teens has hearing loss, study says." To investigate whether this is an appropriate or a misleading headline, you will conduct a test of significance with the following hypotheses: Null: π=0.20 . Alternative: π≠0.20

Required:
a. Describe what the symbol π stands for in this context?
b. Use the Theory-Based Inference applet to determine a p-value.