spee Homework am dun re is no wi E. ble gives the price p (in cents) of a first-class stamp over time where t is the number of years since Number of years since 1970, r Price, P 8 1 1 11 15 18 21 25 29 10 13 15 18 20 22 25 20 32 33 a. Use the linear regression feature of a graphing calculator to find an equation of the best-fitting line for the data. (Round to the hundredth.) Predict the cost of a first-class stamp in 1984. Is this an example of interpolation or extrapolation? c. Predict what year the cost of a first-class stamp was 40 cents. 2. A pumpkin tossing contest is held each year in Morton, Illinois, where people compete to see whose catapult will send pumpkins the farthest. One catapult launches pumpkins from 25 feet above the ground at a speed of different angles. 125 feet per second. The table shows the horizontal distances (in feet) the pumpkins travel when launched at Angle (degrees) 20 30 40 50 60 70 Distance (feet) 372 462 509 501 437 323 a. Use a graphing calculator to find the best-fitting quadratic model for the data. (Round to the hundredth.) b. Use the equation to find the horizontal distance a pumpkin will travel when launched at a 45 degree angle. 3. A study of nutrition in developing countries collected data from the Egyptian village of Nahya. Here are the mean weights for 170 infants in Nahya who were weighed each month during their first year of life. Age (in months) 2 7 8 9 10 11 12 7.5 7.8 Mean Weight (kg) 4.3 5.1 6.3 6.8 7.1 7.2 7.2 7.2 5.7 7.2 a. Find the correlation coefficient for each type of equation. (linear, exponential) round to 4 places b. Which equation best fits the data? 26