Normal distribution worksheet with answers

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

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1.Easy
μ = 178192.35P = ?

The heights of adult men are normally distributed with mean 178 cm and standard deviation 7 cm. What fraction is above 192.35 cm? Find P(X > x) as a decimal.

μ = 178σ = 7x = 192.35
P(X > x) =
2.Easy
−3−2−10123zshaded area to the left of z = 0.3745

Drag z so that the shaded area under the standard normal curve, to the left of z, is 0.3745. Find z to two decimals.

A = 0.3745
z =
3.Medium
480 g484.2 gT = X₁ + … + X₁₂?

The masses of bolts are independent and normal with mean 40 g and standard deviation 1.2 g. Find the probability P that the total mass of 12 of them exceeds 484.2 g. Round z to two decimals.

μ = 40 gσ = 1.2 gn = 12> 484.2 g
P =
4.Medium
70130P = ?

The IQ scores are normally distributed with mean 100 points and standard deviation 15 points. What fraction lies between 70 and 130 points? Give P as a decimal.

μ = 100σ = 15x1 = 70x2 = 130
P =
5.Hard
35455565758595pointsbottom 80%

The exam scores are normally distributed with mean 65 points and standard deviation 10 points. Drag the cut-off so the shaded bottom 80% is to the left of it. Find the cut-off x.

μ = 65 pointsσ = 10 points80%
x = points
6.Hard
557085100115130145pointstop 85%

The IQ scores are normally distributed with mean 100 points and standard deviation 15 points. Drag the cut-off so the shaded top 85% is to the right of it. Find the cut-off x.

μ = 100 pointsσ = 15 points85%
x = points

Answer key

  1. 1. P(X > x) = 0.02018
  2. 2. z = −0.32
  3. 3. P = 0.1562
  4. 4. P = 0.9545
  5. 5. x = 73.4 points
  6. 6. x = 84.4 points

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