From generation to generation, the average age when smokers first start to smoke varies. however, the standard deviation of that age remains constant at around 2.1 years. a survey of 39 smokers of this generation was done to see if the average starting age is at least 19. the sample average was 18.2 with a sample standard deviation of 1.3. do the data support the claim at the 5% level?

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.