A university planner is interested in determining the percentage of spring semester students who will attend summer school.  She takes a pilot sample of 160 spring semester students discovering that 56 will return to summer school. - Using the result of the pilot study with a 0.95 probability, how large of a sample would have to be taken to provide a margin of error of 3% or less?

A sample of 3 medicine bottles is taken from an injection molding machine that is 10% nonconforming. What is the probability of 1 nonconforming medicine bottle in the sample?

In a recent year, the Better Business Bureau settled 75% of complaints they received. You have been hired by the Bureau to investigate complaints this year involving computer stores. You plan to select a random sample of complaints to estimate the proportion of complaints the Bureau is able to settle. Suppose your sample size is 134. What is the probability that the sample proportion will be at most 3 percent more than the population proportion? (Enter your answer as a number accurate to 4 decimal places.)

Suppose a large shipment of laptop computers contained 12% defectives. If a sample of size 286 is selected, what is the probability that the sample proportion will be less than 7% ? Round your answer to four decimal places.