00:01
This problem says in a normally distributed set of data containing 28 ,658 scores, determine the number of scores that fall within the given condition, express your answer as whole numbers.
00:11
So for the first scenario we're asked for the number of scores that would be more than three standard deviations away from the mean.
00:19
And it doesn't say that it's more than three standard deviations away from the mean above or below.
00:24
So what we're looking at is three standard deviations less and three standard deviations more away from the mean as possibly being more than three standard deviations away.
00:33
And what we know from a normal distribution based on the empirical rule is that within three standard deviations less and three standard deviations more, there's 99 .7 % of the observations.
00:47
So if we want to know how many observations are more than three standard deviations away, that means we want everything but that 99 .7%.
00:57
So 1 minus 0 .997, 99 .7 % as a decimal, will give us the proportion in decimal form that's more than three standard deviations away, and that's .003...