Normal Distribution and Standard Deviation |
Lesson 1 |
Problem: Find the percentage of the normally distributed
data that lies within 2 standard deviations of the mean.
Solution Percentages from -2 to +2 standard deviations.
Step 1:
Solution 4.4%+9.2%+15.0%+19.1%+19.1%+15.0%+9.2%+4.4% = 95.4%
Step 2:
Solution
Answer:
95.4%
Step 3:
Complete
Try two practice problems:
Solve the following:
A. |
Johnny’s
scores in a subject this semester were rather inconsistent: 165, 230, 120, 100, 90, 125, 75.For this
population, how many scores are within one standard deviation of the mean? |
B. |
A group of 423
people has a mean age of 16.4 years with a standard deviation of 0.6
years. The ages are normally
distributed. How many people are
younger than 15.2 years? Express
answer to the nearest people? |