1. A statistic is an unbiased estimator of a populationparameter. This means that ...
A. ... the population mean is equal to the mean of theparameter.
B. ... the population is normal and the population mean is equalto the statistic.
C. ... the population is normal, the population mean is equal tothe statistic mean, and the population standard deviation is equalto the parameter standard deviation.
D. ... the statistic mean is equal to the parameter.
2. An online survey was conducted to study cyberbullying in theUK. It was reported that 62% of young people had received nastyprivate messages on a social network. You randomly sample fouryoung people from the network and ask them if they received nastymessages on the network. Find the probability that the number whoreceived these messages is three.
A. .85 B. .36 C. .74 D. .18
3. The number of particles large enough to initiate a crack onan aircraft wing follows a Poisson distribution with mean 0.5 persquare centimeter. Find the probability that a 100 squarecentimeter section has more than 60 of these particles.
A. .270 B. .207 C. .072 D. .027
6. In a survey of 1430 undergraduate students, 1087 reportedthat they had one or more credit cards. Give a 95% confidenceinterval for the proportion of all college students who have atleast one credit card.
A. 73% to 79% B. 70% to 82% C. 65% to 60% D. 74% to 78%
7. A study compared the proportions of young women and men whouse Instagram. Out of 537 women, 328 used Instagram, whereas out of532 men, 234 used the service. Find a 95% confidence interval forthe difference between the proportions of men and women who useInstagram.
A. .09 to .25 B. .10 to .24 C. .11 to .23 D. .12 to .22
8. As a result of the computation of a confidence interval witha 95% confidence level, it is reported that the proportion ofAmerican families that own more than one car is 12.4% with a marginof error of 2%. In light of this, we are 95% confident that thelargest the actual proportion of such families can be is:
A. 14.4% B. 12.6% C. 12.42% D. 16.4%
