How to Calculate Covariance From a TI-84

If you have recently acquired a TI-84 graphing calculator from Texas Instruments, then you may be wondering how to use the calculator to determine complex mathematical equations. For example, you can calculate covariance on a TI-84, which is the measurement of a linear relationship. Learn the basics of inputting data into your TI-84, which functions much like a miniature computer. Memorize the formula for calculating covariance for quick computations.

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A TI-84 calculator makes computing covariance possible.

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Turn on your TI-84 by pressing the "On" button.

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Calculate the mean of each of your variables X and Y. The mean is the average of a set of numbers.

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For example, for this exercise X's data set is (1, 2, 3,4) and Y's data set is (5,6,7,8). Type the following formula and press "Enter" to find the average of X: (1 + 2 + 3 + 4)/4. The average of X is 2.5. Type the following formula and press "Enter" to find the average of Y: (5 + 6 + 7 + 8)/4. The average of Y is 6.5.

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Multiply corresponding data from each set X and Y.

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For example, here are your two sets of data:

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X : 1,2,3,4 Y : 5,6,7,8

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Type into your calculator each of these equations, followed by "Enter" :

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1 X 5 2 X 6 3 X 7 4 X 8

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Your answers will be the following: 5, 12, 21, 32

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Calculate the mean of this set of data: 5, 12, 21, 32

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Type (5 +12 + 21 + 32)/4 and "Enter."

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You will get 17.5.

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Multiply the means of X and Y.

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Type 2.5 X 6.5. Press "Enter."

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Your answer is 16.5.

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Subtract 17.5 - 16.5. Press "Enter."

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Your covariance is 1.