statistics
posted by mary on .
Which of the following numbers could not
possibly be probabilities?
justify your answer
a)0.124
b)1
c)0.1142
d)0
e)2/7
f)6/5
g)2.8

What on earth could a negative probability mean ?
How can you have two probabilities more than 100% 
Assume that the mean score on a certain aptitude test across the nation is 100, and that the standard deviation is 20 points. Find the probability that the mean aptitude test score for a randomly selected group of 150 8th graders is between 99 and 101