Calculator resources and instructions  (Page 16/4)

Graphing calculator instructions

• TI-83 video tutorials are available here: ( Part 1 , Part 2 ).
• The Discrete Mean&Stdev link shows how to calculate a mean and $\text{stdev}$ for a discrete random variable.
• The Outliers link shows how to calculate outliers using the lists.
• The Matrix: TI-89 link shows how to create a matrix using the TI-89 calculator for use in a Test of Independence .
• The Random Numbers link shows how to generate random numbers.
• The Sorting link shows how to sort a list.
• The TI-89 link gives some general instructions for the TI-89 plus linear regression instructions.
• Link to Graphing Calculator Help for Several TI Calculators

Calculating the mean and standard deviation of a discrete probability distribution on the ti-83 and ti-86

• Enter the possible values for your random variable $X$ in list L1 .
• Enter the probabilities for each value of $X$ in list L2 in the position next to the value of $X$ .
• Calculate “One Variable Statistics” for lists L1 and L2 .
• (Do this the same way you calculate one variable statistics for data values and frequencies when given a set of data.)
• The calculator will give the mean as "x-bar" $\mathrm{x̄}$ although we know that this mean is actually $\mu$ because it is the mean of a probability distribution.
• The calculator will give the standard deviation as $\sigma$ which indicates the standard deviation of a probability distribution (as well as the standard deviation of a population).
• The calculator does not give you a value for s because the frequencies you gave it are not whole numbers.

Outlier instructions for the ti-83, 86, and 89 calculators

When you finish going over these instructions, do TEXT problem #5 ("stories" and "height of building") in Ch. 12. One of the points is an outlier.

This explains how to find outliers on various calculators. Suppose the data is (3,5), (6,8), (9,7), (5,20). The xlist is 3, 6, 9, 5 and the ylist is 5, 8, 7, 20. Put the xlist into L1 and the ylist into L2 . Do the linear regression. yhat = 11.2267 - .2133x

For ti-83&86 calculators

• Go back to where you entered the lists L1 and L2 and go to the list name L3 . Enter 11.2267-.2133L1 (You enter the equation at the bottom of the screen where it says L3 . Press Enter . In L3 are the yhat values.
• Arrow to the list name L4 . Enter L2-L3 . Press Enter . (In L4 are the y - yhat values.)
• Arrow to the list name L5 . Enter L4^2 . Press Enter . (In L5 are the (y - yhat)^2 values.)
• Continue by finding the Instructions for the appropriate calculator below (83 or 86):

For ti-83

• Exit to the Home Screen. Clear it. Press 2nd LIST . Arrow to MATH . Press 5:sum . (Press L5 ). Press Enter . You should see 137.1467 (to 4 decimal places). This is the SSE.
• Calculate $s$ . Press the square root symbol and enter (137.1467/2) . (You get the denominator by taking the number of data points and subtracting 2: $\text{4 - 2 = 2}$ .) Press Enter . You should see 8.2809 (to 4 decimal places).
• Multiply 8.2809 by 1.9. You should see 15.7337.
• Press L4 . Press Enter . (Use the arrow keys to scroll through the list.)
• Compare 15.7337 to the absolute values of the numbers in L4 . If any absolute value is greater than or equal to 15.7337, then the corresponding point is an outlier.
• Absolute values of the numbers in L4 are 5.587, 1.947, 2.307, 9.8398. None of them are greater than 15.7337, so no point is an outlier.