Assignment:
Normal Probability Distribution
Brain Pick
The weekly incomes of a large group of middle managers are normally distributed with a mean of $1,500 and a standard deviation of $150. Use the standard normal distribution to calculate the following:
1. Find the probability that a particular weekly income selected at random is between $750 and $1,500?
2. What is the probability that the income is less than $900
3. What is the probability that he income is more than $1100?
4. What is the probability that the income is between $1,000 and $1,800? (Be able to draw a graph to illustrate your results)
5. Find the salary that represents the 50th percentile.
6. Find the salary that represents the 90th percentile.
7. 5% of the salaries are below what value?
8. The top 5% of the salaries are above what value?
9. Between what two values will the middle 50% of the data lie?
10. What percent of the managers make more than $1200 a month?
11. Use the empirical rule to determine the following:
A About 68% of the observations lie between what two values?
B About 95% of the observations lie between what two values?
C About 99% of the observations lie between what two values?
12. Use the standard normal distribution to determine the following
A 68% of the observations lie between what two values?
B 95% of the observations lie between what two values?
C 99% of the observations lie between what two values?
13. Discuss the differences in the results for question 12 and question 11