Texas Instruments TI-60 Owner's Manual page 39

CHAPTER 1-4
STATISTICS
2nd (y'J 2nd (n'J - Predicted Value Keys
Aft»f entering an "X value, pressing tho *nd] |yl key displays Ihe "y"
value mat corresponds with that "a" on the tine that the calculator
determined was the best line through the points Similarly, following a "/•
value with 2nd I l*'] gives the corresponding "x" value
Note : Caution should be used in computing an (Independent! value on
the basis of a y (dependent) value Further, n is not valid to compute a
"y' value on tho basis of an which Is outside the range ot entered 'V
values The predictions which result do not have statistic validity, and Ihe
probability figures that are found are not valid However, trend line analysis
and torcastmg calculations often use these computations to make
predictions or estimations ot probability about the future When performing
such calculations. Ihe actual values may differ from the calculated values
Statistics example
You want lo find me average height for a class of 99 high school students
buf do nof have time to obtain a measurement for every studont
Randomly select a sample of eight students, and measure their heights The
height measurements (In inches) are listed below In ascending order
63. 66 69. 69. 71. 72. 74. 76.
Calculate sample mean, standard deviation (e^,) and variance ((<»„.,)*).
Press
OfF ON
2nd [CSR]
63 S.4 66 Ct!
69 69 Vi. |
71 - • 72 : •
74 £t| WQ5* |
2nd (Mean]
i
2nd jon - 1J
CiwL I**J
Display Comments
0 Clear calculator
2
4
6
8
70
4 208634246
17.71428571
Enter data values
Calculate mean
Calculate standard deviation
Calculate variance
For the sample of eight measurements, the average height lor the class is
70 inches, the standard deviation is about 4.2, and ihe variance is about
17.7
29-GB