A recent Pew Center Research survey revealed that 68% of highschool students have used tobacco related products. Suppose astatistician randomly selected 20 high school students. Use thisinformation to answer questions 39-41.

1. To find the probability that exactly 15 used tobacco products,would you use the Binomial, Geometric, or Poisson distribution tofind the probability?
2. Set up the problem to find P (X = 15) using the appropriatedistribution. Do NOT solve.
3. What is the expected number of high school students in thesample who have used tobacco products?

For a self check out at the local Walmart, the mean number ofcustomers per 5 minute interval is 1.5 customers. Use thisinformation to answer questions 42 and 43.

1. To find the probability of 2 customers in the next 5 minutes,would you use the Binomial, Geometric, or Poisson distribution tofind the probability?
2. What is the variance (numeric value)?  

Assuming the grades on the first homework are nearly normal withN(90, 4.3), what proportion of grades fall between 85 and 90?
Assuming the grades on the final exam are nearly normal with N(90,4.3), for a grade of 95 or more on the exam, find the z-score andexplain what it means.
Assuming the grades on the final exam are nearly normal with N(90,4.3), what is the minimum grade putting you in the top 15% of theclass?
Assuming the grades on the final exam are nearly normal with N(82,3.86), what proportion of grades fall between 85 and 90?