Normal ProbabilityThe Seeing Statistics applet on this page may be used to answer Exercises 6.1 to 6.57 in Just the Essentials of Elementary Statistics. When this page initially loads, the applet is set for Exercise 6.15.a. |
Return to Normal Probability Page | |
|
How-To: Enter beginning and ending z-scores in the Start and End boxes. The figure is redrawn and the new probability is calculated after hitting the return key while the cursor is in one of the boxes. For open-ended ranges (e.g., finding the probability that an observations will have z-score greater than -1.55 as in Exercise 6.17.b), use a very large number for the other end. For z-scores, -10 and 10 are very large. |
||
|
For Exercises 6.31 to 6.57, change the numbers in the Mean and StDev boxes to match
the particular problem and then enter the appropriate Start and End values. For example,
for illustration 6-10 (on p. 254), enter 100 in the Mean box, 16 in the StDev box, 100
in the Start box, and 115 in the End box. Remember to hit the Return key in the last box
you enter to start the calculations and redrawing.
Note: Use of tables as illustrated in 6-10 necessarily involves rounding. Hence, the probability in the textbook of 0.3264 does not quite agree with the probability of 0.3257 reported by the applet. The applet does far less rounding and so is more accurate. |
Return to Normal Probability Page |
WARNING: The graph above gives accurate normal probabilities suitable for educational purposes such as homework problems. It is not intended for and should not be used for any calculations which have any major consquences for health, safety, financial matters, etc.
The above applet is from the section "Working with the Normal Distribution" in Seeing Statistics by Gary McClelland. For more information, visit Seeing Statistics
© 1999, Duxbury Press