- If a random variable x is normally distributed, you can find the probability that x will fall in a given interval by calculating the area under the normal curve for the given interval.
- To find the area under any normal curve, first convert the upper and lower bounds of the interval to a z-scores. Then use the standard normal distribution to find the area.
- Another way to find normal probabilities is to use a calculator or a computer. You can find normal probabilities using Minitab, Excel, and the TI-83.
Find the z-score corresponding to a raw score of 132 from a normal distribution with mean 100 and standard deviation 15.
Answer:
132 - 100
z = = 2.133
15
Websites:
http://mathbits.com/MathBits/TISection/Statistics2/normaldistribution.htm
http://stattrek.com/online-calculator/normal.aspx
http://www.intmath.com/counting-probability/14-normal-probability-distribution.php
https://statistics.laerd.com/statistical-guides/normal-distribution-calculations.php
http://www.dummies.com/how-to/content/how-to-find-statistical-probabilities-in-a-normal-.html