Line of Best FitLinear Regression

Entering Data : TI 30X

1. 2nd DATA choose 2-VAR2. DATA (enter data and use down arrow)3. STAT VAR4. Arrow over to find5. a = b = r =6. The equation of the line is y = ax + b. 7. Correlation Coefficient is r.8. To predict use a(predict #) + b. Estimated

method

Entering Data : TI 36X - Pro

1. DATA (type in data)2. 2nd DATA3. 2 VAR L1 L2 Frequency of 1 Calc4. a = b = r = 5. The equation of the line is y = ax + b.6.Correlation Coefficient is r.7.To predict use a(predict #) + b. Estimated

method

You can use the x variable button to find a and b

Example 1: The table shows the total outstanding

consumer debt (excluding home mortgages) in billions of dollars in selected years.

(Data is from the Federal Reserve Bulletin.)

Let x = 0 correspond to 1985.

Year 1985

1990

1995

2000

2003

Consumer Debt 585 789 109

61693

1987

a) Find the regression equation appropriate for this data set. Round values to two decimal places. y 79.86x 463.35

Example 1:

Year 1985

1990

1995

2000

2003

Consumer Debt 585 789 109

61693

1987

b) Find and interpret the slope of the regression equation in the context of the scenario.

79.86 represents the increase in consumer debt each year.

c) Find the approximate consumer debt in 1998.

$1501.53 billion

d) Find the approximate consumer debt in 2008.

$2300.13 billion

Example 2: The table below shows the number of deaths per

100,000 people from heart disease in selected years.

(Data is from the U.S. National Center for Health Statistics.)

Let x = 0 correspond to 1960. Year 1960 1970 1980 1990 2000 2002

Deaths

559 483 412 322 258 240

a) Find the regression equation appropriate for this data set. Round values to two decimal places. y 7.62x 559.25

Example 2:

b) Find and interpret the slope of the regression equation in the context of the scenario.

-7.62 is the decrease in deaths caused by heart disease each year.

c) Find the approximate number of deaths due to heart disease in 1995. 293 deaths

d) Find the approximate number of deaths due to heart disease in 2008.

194 deaths

Year 1960 1970 1980 1990 2000 2002

Deaths

559 483 412 322 258 240

ClassworkLinear Regression