PDA

View Full Version : Need help with statistics question...


jda1509
Jan 5, 2011, 09:40 PM
Mean height of men, mean 68 inches and a standard deviation of 2.5 inches.
What is the probability of a man selected at random will have a hight above 72 inches?
A sample of 49 meant, what is the probaility that the mean hight is greater than 67 inches (using standard score table)?

Unknown008
Jan 9, 2011, 12:19 AM
By standard score table, you mean the Normal Distribution?

If so, first define your variable, that is the height.

Let X be the height of a man.

X \sim N(68, 2.5^2)

Then, P(X > 75) = P(z > \frac{75 - 68}{2.5})

Find the z-score and look up your table for the corresponding probability. Make a sketch if needed to confirm your answer.