your class average on a test was a 70 with a standard deviation of 3 points.What percent of the class fell between 67 and 76 points
your class average on a test was a 70 with a standard deviation of 3 points.What percent of the class fell between 67 and 76 points
I am going to split this into 2 parts. Below the mean and above the mean.
70-3=67 so 67 is one standard deviation below the mean
between -1 and +1 SD from the mean lie 64% of all scores. Half of this is 34%
70+2*3=76 and 76 is 2 standard deviations above the mean.
between -2 and +2 SD from the mean lie 95% of all scores. Half of this is 47.5%
Total prob of lying in desired region = 34+47.5 = 81.5% approximately.
your class average on a test was a 70 with a standard deviation of 3 points.What percent of the class fell between 67 and 76 points
I am going to split this into 2 parts. Below the mean and above the mean.
70-3=67 so 67 is one standard deviation below the mean
between -1 and +1 SD from the mean lie 64% of all scores. Half of this is 34%
70+2*3=76 and 76 is 2 standard deviations above the mean.
between -2 and +2 SD from the mean lie 95% of all scores. Half of this is 47.5%
Total prob of lying in desired region = 34+47.5 = 81.5% approximately.