2) Can you get cat and red at the same time? Have you got a formula for this type of probability?
4) Have you learned the rules regarding 68,95,99 ?
Show us your worth so far, so that we can find your errors.
3. The computer club has 100 members. There are 50 women and 50 men. Thirty of the women are 21 years of age and older, 45 of the men are 21 years of age and older. What is the probability that a member who is 21 or older and selected at random will be a woman?
4.The mean salary for the engineering department of a large company is $100,000. The salaries for the engineering department follow a normal distribution. About 95% of the salaries are between $60,000 and $140,000. What is the standard deviation of the salaries for the engineering department?
3. Pr(woman | over 21) = Pr(woman and over 21)/Pr(over 21).
Pr(woman and over 21) = .....
Pr(over 21) = ....
4. See this thread for a similar question: http://www.mathhelpforum.com/math-he...deviation.html