The amounts of a chemical compound y that dissolved in 100 grams of water at various temperatures x were recorded. Use the given data to complete parts (a) through (c) below. Click the icon to view the recorded data. (a) Find the equation of the regression line. (Round the constant to two decimal places as needed. Round the coefficient to three decimal places as needed.) (b) Graph the line on a scatter diagram. Choose the correct graph below. ○ A. Grams 90- ✓ О в. Grams 60- 0+ 0 80 Temperature (C) 80 Temperature (C) (c) Estimate the amount of chemical that will dissolve in 100 grams of water at 50°C. ŷ= grams (Round to two decimal places as needed.) ✓ ос. Grams 60- 0 0 80 Temperature (C) ✓ ○ D. Grams 60- 0 80 Temperature (C) ✓ Chemical compound data x (degrees °C) n y (grams) 0 7 6 7 15 30 45 60 75 22044 12 25 30 45 47 22333 10 15 20 23 35 26 38 41 53 45

The following fictitious table shows kryptonite price, in dollar per gram, t years after 2006. t= Years since 2006 0 1 2 3 4 5 6 7 8 9 10 K= Price 56 51 50 55 58 52 45 43 44 48 51 Make a quartic model of these data. Round the regression parameters to two decimal places.

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?

For the following exercises, consider the data in Table 5, which shows the percent of unemployed in a city ofpeople25 years or older who are college graduates is given below, by year. 41. Based on the set of data given in Table 7, calculatethe regression line using a calculator or othertechnology tool, and determine the correlationcoefficient to three decimal places.