3.28 chickenpox, part ii. we learned in exercise 3.26 that about 90% of american adults had chickenpox before adulthood. we now consider a random sample of 120 american adults. (a) how many people in this sample would you expect to have had chickenpox in their childhood? and with what standard deviation? (b) would you be surprised if there were 105 people who have had chickenpox in their childhood? (c) what is the probability that 105 or fewer people in this sample have had chickenpox in their childhood? how does this probability relate to your answer to part (b)?

Data for the height of a model rocket launch in the air over time are shown in the table. darryl predicted that the height of the rocket at 8 seconds would be about 93 meters. did darryl make a good prediction? yes, the data are best modeled by a quadratic function. the value of the function at 8 seconds is about 93 meters. yes, the data are best modeled by a linear function. the first differences are constant, so about 93 meters at 8 seconds is reasonable. no, the data are exponential. a better prediction is 150 meters. no, the data are best modeled by a cubic function. a better prediction is 100 meters.