Question

You are a researcher studying the lifespan of a certain species of bacteria. A preliminary sample of 35 bacteria reveals a sample mean of ¯x=74x¯=74 hours with a standard deviation of s=6.8s=6.8 hours. You would like to estimate the mean lifespan for this species of bacteria to within a margin of error of 0.55 hours at a 90% level of confidence.

What sample size should you gather to achieve a 0.55 hour margin of error? Round your answer up to the nearest whole number.

n =_____ bacteria

Insurance companies are interested in knowing the population percent of drivers who always buckle up before riding in a car. They randomly survey 416 drivers and find that 317 claim to always buckle up. Construct a 89% confidence interval for the population proportion that claim to always buckle up. Use interval notation, for example, [1,5]

Answer 1