Excel does regressions. Do you have Excel?.

Let t=0 be 1965

A quadratic regression works pretty well.

Results 1 to 6 of 6

- August 16th 2008, 03:17 PM #1

- Joined
- Jul 2008
- Posts
- 38

## Sorry! This one...thanks

**Year****Average Poverty Threshold (in $)**

1965 3022

1970 3223

1975 3968

1980 5500

1985 8414

A.) Find a model for this data

B.) Estimate the average poverty threshold for a family of four in 1990

C.) Give a reasonable Domain and Range

- August 16th 2008, 03:31 PM #2

- August 16th 2008, 03:45 PM #3

- Joined
- Jan 2008
- From
- Big Stone Gap, Virginia
- Posts
- 2,551
- Thanks
- 14
- Awards
- 1

- August 17th 2008, 01:18 PM #4

- Joined
- Jul 2008
- Posts
- 38

- August 17th 2008, 01:36 PM #5

- Joined
- Jan 2008
- From
- Big Stone Gap, Virginia
- Posts
- 2,551
- Thanks
- 14
- Awards
- 1

What tools do you have at your disposal?

**Galactus**said he used**Excel**from Microsoft Office. I've never used**Excel**for that before. Maybe**Galactus**can elaborate.

Of course, the long way would be the algebraic, paper, pencil way.

I used a TI-84+ calculator to plot the data. I observed the data seemed to follow a parabolic curve. I performed a quadratic regression analysis to find the best quadratic equation that would best fit the curve. The equation I produced had a coefficient of determination of .9964. The closer this number is to 1, the better. This means the curve produced by my equation is pretty accurate.

- August 17th 2008, 01:44 PM #6

- Joined
- Jul 2008
- Posts
- 38