A corporation has 15,000 employees. Sixty-two percent of the ...

[frankwu]

A corporation has 15,000 employees. Sixty-two percent of the employees are male. Twenty-three percent of the employees earn more than 30,000 a year. Eighteen percent of the employees are male and earn more than 30,000 a year.
 a. If an employee is taken at random, what is the probability that the employee is male?
  b. If an employee is taken at random, what is the probability that the employee earns more than 30,000 a year?
  c. If an employee is taken at random, what is the probability that the employee is male and earns more than 30,000 a year?
  d. If an employee is taken at random, what is the probability that the employee is male or earns more than 30,000 a year or both?
  e. The employee taken at random turns out to be male. Compute the probability that he earns more than 30,000 a year.
  f. Are being male and earning more than 30,000 a year independent?

Question 2

A random sample of 16 students selected from the student body of a large university had an average age of 25 years and a standard deviation of 2 years. We want to determine if the average age of all the students at the university is significantly more than 24 . Assume the distribution of the population of ages is normal. Using  = .05, it can be concluded that the population mean age is
 a. not significantly different from 24.
   b. significantly different from 24.
   c. significantly less than 24.
   d. significantly more than 24.

[IRincones]

Answer to Question 1

a. .62
b. .23
c. .18
d. .67
e. .2903
f. No

Answer to Question 2

d