statistics | Statistics homework help

 Computing Probabilities with the Central Limit Theorem 

18. High school graduates: The National Center for Educational Statistics reported that 82% of freshmen entering public high schools in the U.S. in 2009 graduated with their class in 2013. A random sample of 135 freshmen is chosen.

c. Find the probability that less than 80% of freshmen in the sample graduated.

d. Find the probability that the sample proportion of students who graduated is between 0.75 and 0.85.

 The Normal Approximation to the Binomial Distribution 

20. Gardening: A gardener buys a package of seeds. Eighty percent of seeds of this type germinate. The gardener plants 90 seeds.

b. Approximate the probability that 80 or more seeds germinate.