Parameters and hypotheses. For each of the following situations, define the parameter (proportion or mean) and write the null and alternative hypotheses in terms of parameter values. Example: We want to know if the proportion of up days in the stock market is 50%. Answer: Let p = the proportion of up days. H0: p = 0.5 vs. HA: p  0.5.

a) A casino wants to know if their slot machine really delivers the 1 in 100 win rate that it claims.

b) Last year, customers spent an average of $35.32 per visit to the company’s website. Based on a random sample of purchases this year, the company wants to know if the mean this year has changed.

c) A pharmaceutical company wonders if their new drug has a cure rate different from the 30% reported by the placebo.

d) A bank wants to know if the percentage of customers using their website has changed from the 40% that used it before their system crashed last week.