An urn contains four red balls, five yellow balls, and seven green balls. You randomly select two balls without replacement. Express your answer as a decimal rounded to four decimal places. a.) What is the probability they are both green? [a] b.) What is the probability the first ball is green and the second ball is yellow? [b]
Read DetailsA national polling organization does a survey of 995 people to estimate the percentage of all American adults who favor a ban on the use of cell phones while driving. In the survey, 37% said they favor such a ban. a.) Find a 90% confidence interval for the proportion of all American adults who favor such a ban. Also find the margin of error. Round your answers to four decimal places. 90% Confidence Interval: ( [LL] , [UL] ) Margin of Error: [E] b.) Still using a 90% confidence interval, how many should be polled to reduce the margin of error to 2%? Use the fact that in the first poll 37% said that they favor such a ban. Required sample size = [n]
Read DetailsAn Olympic archer is able to hit the bull’s eye 75% of the time. Suppose she shoots 25 arrows. For a – c, express your answer as a decimal rounded to four decimal places. a.) What is the probability she gets exactly 19 bull’s eyes? [a] b.) What is the probability that she gets at most 16 bull’s eyes? [b] c.) What is the probability that she gets at least 14 bull’s eyes? [c] d.) If she shot 25 arrows many times, what is the mean and standard deviation of how many bull’s eyes she would get? Round to one decimal place, if appropriate. Mean = [mean] Standard Deviation = [sd]
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