Determining the probability from the given situation.

A stack of 12 papers contains three "A" papers. If three papers are selected, what is the probability a) All three are "A" papers? b) None are "A" papers?

Determining the probability from the given ball situation.

A box contains 7 red, 3 green and 5 blue balls. a) If one ball is drawn at random, find the probability it is red. b) If two balls are drawn, find the probability both are green c) If two balls are drawn, find the probability one is red and the other is blue d) If two balls are drawn, find the probability both are red or both are green. e) If two balls are drawn, find the probability at least one is red.

Standard deviation

Find the standard deviation of the data in the given frequency table. A company had 80 employees whose salaries are summarized in the frequency table below. Find the standard deviation. Salary Employees 5001-10000 17 10001-15000 16 15001-20000 20 20001-25000 15 25001-30000 12

Determining the probability from a given situation.

An elevator has 4 passengers and 8 floors. Find the probability that no 2 passengers get off on the same floor considering that it is equally likely that a person will get off at any floor.

Probability

A die is rolled 20 times and the number of twos that come up is tallied. Find the probability of getting the given result. More than one two.