# need help solving this probability question.

• Apr 12th 2011, 04:58 AM
axz92
need help solving this probability question.
Hey again guys.

The previous question i posted in the forum was already solved, but i have another question.

how do i solve:

What is the probability that a randomly selected ping pong ball will have a diameter between 2.28 and 2.30 inches?

Given: mean 2.3 inches and standard deviation of 0,04 inch.

Thanks.
• Apr 12th 2011, 05:33 AM
SpringFan25
What distribution does that question tell you to use?

If it's the normal distribution, then you need no skill to calculate a probability beyond what you already used to solve the question in your other thread.
• Apr 12th 2011, 05:33 AM
mr fantastic
Quote:

Originally Posted by axz92
Hey again guys.

The previous question i posted in the forum was already solved, but i have another question.

how do i solve:

What is the probability that a randomly selected ping pong ball will have a diameter between 2.28 and 2.30 inches?

Given: mean 2.3 inches and standard deviation of 0,04 inch.

Thanks.

I assume diameter is a normal random variable.

Convert D1 = 2.28 and D2 = 2.30 into Z-values z1 and z2 using $\displaystyle Z = \frac{D - \mu}{\sigma}$. Then calculate Pr(z1 < Z < z2) in the usual way (you were shown this in your other thread http://www.mathhelpforum.com/math-he...ns-176862.html).

If you need more help, show all your working and say where you get stuck.