Education Technology

# Knowledge Base

## Solution 34799: Calculating the Confidence Interval for Slope on the TI-84 Plus Family of Graphing Calculators.

### How can I calculate the confidence interval for slope on the TI-84 Plus family of graphing calculators?

To calculate the confidence interval for a slope follow the example below:

Example:

L1: {4,5,6,7,8}
L2: {1,2,3,3.5,4.5}

Solution:

• Press [STAT] [ENTER] to enter the STATS editor.
• Press [4] [ENTER] [5] [ENTER] [6] [ENTER] [7] [ENTER] [8] [ENTER].
• Press [►].
• Press [1] [ENTER] [2] [ENTER] [3] [ENTER] [3] [.] [5] [ENTER] [4] [.] [5] [ENTER].

• Press [2ND] [QUIT].
• Press [STAT].
• Press [►] [►] to select the TESTS Menu.
• Select G:LinRegTInt...

• Press [2ND] [L1] [ENTER] for Xlist.
• Press [2ND] [L2] [ENTER] for Ylist.
• Press [1] [ENTER] for Freq.
• Press [.] [9] [5] [ENTER] for C-Level.
• Press [VARS] [►].
• Press [ENTER] [ENTER], Y1 will be pasted next to RegEQ: to show that the regression equation will be stored under Y1.

• Press [ENTER] [ENTER] to display the results.
• Press [▼] to view additional results.

• Press [GRAPH] to see the regression.