Math Literacy



Name:_________________ Linear Regression Practice Assignment:_______

Directions: Answer each question and round answers to the hundredths place.

Linear Regression Model: This is often known as the line of best fit which is a line used to model a set of data. A line of fit shows the general direction of the data and has about the same number of data points above and below it.

|x |y |

|17 |34 |

|18 |49 |

|38 |90 |

|40 |96 |

|29 |70.5 |

|16 |41.5 |

|11 |33 |

Example: Find the linear regression model using your calculator of the data.

Step 1: Enter the data into the L1 and L2 in your calculator.

Step 2: Graph the scatterplot. Make sure your StatPlots are turned on. Change the window if necessary.

Step 3: Calculate the linear regression model (shown to the right)

stat→calc→8 → L1 → , → L2 → , → VARS →Y-VARS → enter → enter → enter

Step 4: Record the linear regression model. y =

Step 5: Press graph and view the linear regression line on your scatterplot

1. The following data represents the amount of money Sergio has in his bank account.

|Week |1 |

|Xmax | |

|Xscl | |

|Ymin | |

|Ymax | |

|Yscl | |

a) Find the Linear Regression model and graph your model

stat→calc→8 → L1 → , → L2 → , → VARS →Y-VARS → enter → enter → enter

y = ____________________

b) Based on the equation for the linear regression line, what is your slope and y-intercept?

Slope: ____________ y-intercept: _______________

c) What is the real-world meaning of the slope?

d) What is the real-world meaning of the y-intercept?

e) Use the equation to calculate when Sergio will be out of money.

2. The following table represents the number of calories and grams of fat certain food items contain.

|Grams of |6 |

|Fat | |

|Xmax | |

|Xscl | |

|Ymin | |

|Ymax | |

|Yscl | |

a) Graph the data on a scatterplot and describe the window you used in the table.

b) Find the Linear Regression model y = ____________________

c) Based on the equation for the linear regression line, what is your slope and y-intercept? Slope: ____________ y-intercept: ___________

d) What is the real-world meaning of the slope?

e) What is the real-world meaning of the y-intercept? Does this make sense?

f) According to the model, approximately how many grams of fat (x) are in a burger that has 334 calories? Show your work.

|Year |1992 |

|Xmax | |

|Xscl | |

|Ymin | |

|Ymax | |

|Yscl | |

a) Graph the data on a scatterplot and describe the window you used in the table.

b) Find the Linear Regression model y = ____________________

c) Based on the equation for the linear regression line, what is your slope and y-intercept?

Slope: ___________________ y-intercept: _______________

d) What is the real-world meaning of the slope?

e) Approximately how many part-time jobs are there this year (2009)? Show your work.

f) When will the number of part-time jobs reach 8 million? Show your work.

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