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How to Calculate Statistical Slope Percent

Calculating the statistical slope, or line of an equation from data, is called linear regression. Data that works well for linear regression looks like a dot-to-dot line on a scatter graph. It doesn't matter if your data is about percents, time, quantities, people, or if it's a statistic about people or plants, the method is the same for all data types. The mathematics for linear regression is tedious and time consuming: with a TI83 calculator, you can have your answer in minutes.

Data set with inputs and outputs (for example, a list of x-values and their related y-values)

Instructions

- 1
  Press the "Stat" button.
- 2
  Scroll to the first column in list "l1" using the scroll keys.
- 3
  Enter your first "x" value. Press "Enter."
- 4
  Enter your second "x" value. Press "Enter."
- 5
  Continue entering your x-values, pressing "Enter" after each entry.
- 6
  Scroll to the top of list "l2."
- 7
  Enter all of your "Y" values in the same way that you entered your "X" values.
- 8
  Press "2nd" then "Y=."
- 9
  Press the "Enter" key. "PLOT 1" should be highlighted. If it isn't, use the cursor keys to highlight it.
- 10
  Highlight "On" and then press "Enter."
- 11
  Select the "Scatterplot" type (a graph with dots).
- 12
  Type "l1" into "Xlist" and "y1" into "Ylist" l2. Press "Enter" after each selection.
- 13
  Highlight the small box at the left for "Mark." Press "Enter," and then press "Graph." Your calculator will graph a scatterplot with your data.
- 14
  Calculate the linear regression. Press the "Stat" key. Use the cursor keys to move to "Calc," and then press "8:LinReg(a+bx)." Press "VARS, right-arrow," and then press "Enter." The data for the equation for your line will appear on your screen.

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