A pharmacist believes that the active ingredient in medicine decreases linearly over time. To test this, a random sample of 6 medicines were selected and the concentration of active ingredient was measured, in milligrams (mg). Three months later, the concentration of active ingredient was measured again. For cach medicine, the beginning and ending amount of active ingredien is listed in the table. Beginning active ingredient (mg) Ending active ingredient (mg) 200 230 285 325 390 410 Which of the following is the value of the correlation between the beginning concentration of active ingredient 170 225 230 260 290 310 and the ending concentration of active ingredient? O 0.937 O-0.937 O 0.968 -0.968 Cannot be determined because the concentration of active ingredient is not quantitative.

Table 6 shows the population, in thousands, of harbor seals in the Wadden Sea over the years 1997 to 2012. a. Let x represent time in years starting with x=0 for the year 1997. Let y represent the number of seals in thousands. Use logistic regression to fit a model to these data. b. Use the model to predict the seal population for the year 2020. c. To the nearest whole number, what is the limiting value of this model?

Table 2 shows a recent graduate’s credit card balance each month after graduation. a. Use exponential regression to fit a model to these data. b. If spending continues at this rate, what will the graduate’s credit card debt be one year after graduating?

Find the equation of the regression line for the following data set. x 1 2 3 y 0 3 4

Olympic Pole Vault The graph in Figure 7 indicates that in recent years the winning Olympic men’s pole vault height has fallen below the value predicted by the regression line in Example 2. This might have occurred because when the pole vault was a new event there was much room for improvement in vaulters’ performances, whereas now even the best training can produce only incremental advances. Let’s see whether concentrating on more recent results gives a better predictor of future records. (a) Use the data in Table 2 (page 176) to complete the table of winning pole vault heights shown in the margin. (Note that we are using x=0 to correspond to the year 1972, where this restricted data set begins.) (b) Find the regression line for the data in part ‚(a). (c) Plot the data and the regression line on the same axes. Does the regression line seem to provide a good model for the data? (d) What does the regression line predict as the winning pole vault height for the 2012 Olympics? Compare this predicted value to the actual 2012 winning height of 5.97 m, as described on page 177. Has this new regression line provided a better prediction than the line in Example 2?

Can the average rate of change of a function be constant?