# Quiz 3 Solutions - STAT 225 Quiz 3 Mon Feb 24 2014...

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1 STAT 225, Quiz 3 Mon. Feb. 24, 2014 Name (please print) ________________________ Class Time: _________________ Directions: You have 10 minutes to complete the quiz. Show all work to receive full credit. Instructors will not interpret questions for you. Write out the probability statement and show work. Use 4 decimal places in your answers. A recent survey of American households showed that 70% engage in some level of "spring cleaning". To verify the findings of this survey, you randomly ask 20 people whether anyone in their household engages in spring cleaning. Assume all individuals responding are independent from each other. Let X be the number of respondents in the sample stating that someone in their household does spring cleaning. a)State the distribution and parameter(s) for X. What values can X take on? (4 pts)
b)What is Var(X)? (3 pts)
c)What is the probability that 15 people in your sample state that someone in their household engages in spring cleaning? (4 pts)
d)You have a business cleaning houses and offer to do the spring cleaning for each person in your sample who states that no one in the household does spring cleaning. (Assume that everyone who did not do their own spring cleaning will say yes to your cleaning offer). You will charge \$75 per household. What do you expect to earn? (4 pts)
2 STAT 225, Quiz 3 Mon. Feb. 24, 2014