The manager of a supermarket found that 72% of the shoppers who taste a free sample of a food item will buy the item. What is the expected number of shoppers that will buy the item if a random sample of 50 shoppers taste a free sample?

According to the historical data, the life expectancy in Argentina is equal to the life expectancy in Bolivia. A new study has been made to see whether this has changed. Records of 225 According to the historical data, the life expectancy in Argentina is equal to the life expectancy in Bolivia. A new study has been made to see whether this has changed. Records of 225 individuals from argentina who died recently are selected at random. The 225 individuals lived an average of 77.4 years with a standard deviation of 6.7 years. Records of 300 individuals from Ireland who died recently are selected at random and independently. The 300 individuals lived a mean of 76.5 years with a standard deviation of 5.3 years. Assume that the population standard deviations of lifetimes in these two countries can be estimated by the sample standard deviations, as the samples used were quite large. Construct a 90% confidence interval for , the difference between the life expectancy in the United States and…

Twelve married couples participate in a tournament. The group of 24 people is randomly split into each eight teams of three people each. What is the expected value of the number of teams with a married couple?

Approximately 10% of all people are left-handed.  If you select a group of 27 people, what is the expected number of those selected that are left handed?