9/28/10 Week 6
Continuous Random Variable the normal random variable
Bell shaped, empirical rule
68% of observations were within 1 standard deviation of the mean
95% of the observations were within 2 standard deviations of the mean
99.7% of the observations were within 3 standard deviations of the mean
Normal Distribution is a special bell shape where we can use table A1 to find probabilities after
converting some observed score to a z score
Z score formula: observed mean/ standard deviation
Z score the number of standard deviation an observation falls from the mean
Work of off the mean
Ex. MCAT out of 45 hypothetically mean is 35 with standard deviation of 3 and is adjusted to follow
a normal distribution or approximately more.
You want to get into University of North Carolina at Chapel Hill and they look for students who
score 40 or higher on MCAT.
What is the probability of you scor