Probability worksheet with answers

Free printable Probability worksheet: 6 problems from easy to exam level, with an answer key. Print it or save it as a PDF.

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Name: ____________________   Date: ____________

1.Easy
red: 4blue: 5green: 3

A bag holds 4 red, 5 blue and 3 green balls. You draw one at random. What is the probability P that it is blue?

4 / 5 / 3
P =
2.Easy
red: 8blue: 3green: 5

A bag holds 8 red, 3 blue and 5 green balls. You draw one at random. What is the probability P that it is red?

8 / 3 / 5
P =
3.Medium
xp(x)00.1510.1520.1530.2540.3μ = 2.4

For the distribution shown, find the standard deviation σ of X.

x: 0, 1, 2, 3, 4p(x): 0.15, 0.15, 0.15, 0.25, 0.3
σ =
4.Medium
n = 14k = 2N = ?

In how many ways N can a committee of 2 people be chosen from a group of 14? The order does not matter.

n = 14k = 2
N =
5.Hard
xp(x)00.0510.220.230.340.25μ

X has the distribution shown, and Y = −2X + 1. Find the standard deviation σY of Y.

x: 0, 1, 2, 3, 4p(x): 0.05, 0.2, 0.2, 0.3, 0.25Y = −2X + 1
σY =
6.Hard
n = 6, p = 0.5: P(X = 5) = ?k0123456

A test has 6 multiple-choice questions. A student who guesses gets each one right with probability 0.5, independently. What is the probability P of exactly 5 correct answers?

n = 6p = 0.5k = 5
P =

Answer key

  1. 1. P = 0.4167
  2. 2. P = 0.5
  3. 3. σ = 1.428
  4. 4. N = 91
  5. 5. σY = 2.408
  6. 6. P = 0.09375

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