Food You research the average cost of whole milk for several recent years to look for trends. The table shows your data.
Year | 1998 | 2000 | 2002 | 2004 | 2006 | 2008 |
---|---|---|---|---|---|---|
Average cost for one gallon ($) | 2.65 | 2.89 | 3.00 | 3.01 | 3.20 | 3.77 |
SOURCE: U.S. Department of Agriculture
What is the equation for the line of best fit? How accurate is your line of best fit?
Step 1
Use the STAT feature to enter the data in your graphing calculator. Enter the x-values (year) in L1 and the y-values (price) in L2. Let 1997 = year 0.
Step 2
Use LinReg to find the linear regression line of best fit for the data.
Based on your linear model, how much would you expect to pay for a gallon of whole milk in 2020?
What factors could affect the accuracy of your prediction?
Predictions based on strongly correlated data are likely to be more reliable than predictions based on weakly correlated data.
In 2020, you would expect to pay about $4.60 for a gallon of whole milk.
The table lists the cost of 2% milk. Use a scatter plot to find the equation of the line of best fit. Based on your linear model, how much would you expect to pay for a gallon of 2% milk in 2025?
Year | 1998 | 2000 | 2002 | 2004 | 2006 | 2008 |
---|---|---|---|---|---|---|
Average cost for one gallon ($) | 2.57 | 2.83 | 2.93 | 2.93 | 3.10 | 3.71 |
SOURCE: U.S. Department of Agriculture