Assume that a sample is used to estimate a population proportion p. Find the 80% confidence interval for a sample of size 269 with 221 successes. Enter your answer as a tri-linear inequality using decimals (not percents) accurate to three decimal places.

The effectiveness of a blood-pressure drug is being investigated. An experimenter finds that, on average, the reduction in systolic blood pressure is 85.6 for a sample of size 318 and standard deviation 6.5.Estimate how much the drug will lower a typical patient's systolic blood pressure (using a 98% confidence level).Enter your answer as a tri-linear inequality accurate to one decimal place (because the sample statistics are reported accurate to one decimal place). < μ < Answer should be obtained without any preliminary rounding.

In a survey of 952 respondents, 620 of them voted in a recent election. Find a 95% confidence interval estimate for the true population proportion that voted in this election.

Suppose that there is a 15% chance that a randomly selected Stat 240 student wears glasses. Out of a class with 35 students, what is the minimum number of students wearing glasses for the percent to be considered unusually high?   Thanks!

A local cellular phone company wishes to estimate the proportion of Clinton County people who own a cellular phone. A previous study showed the proportion to be about 25%. What is the minimum number of people that should be randomly selected so the cellular company is 95% confident that the estimate is within 5% of the true proportion of cellular phone users?

Before every flight, the pilot must verify that the total weight of the load is less than the maximum allowable load for the aircraft.  The aircraft can carry 42 passengers,  and a flight has fuel and baggage that allows for the total passenger load of 6,972lb. The pilot sees that the plane is full and all the passengers are men. The aircraft will be overloaded if the mean weight of the passengers is greater than 6,972lb/42=166lb. What is the probability that the aircraft is overloaded? Should the pilot take any action to correct for an overloaded aircraft? Assume that the weights of men are normally distributed with a mean of 176.9lb and a standard deviation of 37.7. THE probability is approximately.               ? Round to four decimal places.

The effectiveness of a blood-pressure drug is being investigated. An experimenter finds that, on average, the reduction in systolic blood pressure is 75.7 for a sample of size 640 and standard deviation 17.9. Estimate how much the drug will lower a typical patient's systolic blood pressure (using a 98% confidence level). Enter your answer as a tri-linear inequality accurate to one decimal place (because the sample statistics are reported accurate to one decimal place). < 4 < Answer should be obtained without any preliminary rounding.

Suppose 500 different researchers all randomly select samples of n = 300 individuals from a population. Each researcher uses his or her sample to compute a 95% confidence interval for the proportion who have blue eyes in the population. About how many of the confidence intervals will cover the population proportion? About how many of the intervals will not cover the population proportion? Briefly explain how you determined your answers. About About which is % of the 500 computed intervals, should contain the population proportion. which is % of the 500 computed intervals, should not contain the population proportion.

Researchers are looking to see what proportion of students will report cheating if they see it happen. A SRS of 172 undergraduates is collected and 19 respond that they would report cheating if they saw it happen. What is the point estimator?