Example:
Professor Halen has 184 students in his college mathematics lecture class. The scores on the midterm exam are normally distributed with a mean of 72.3 and a standard deviation of 8.9. How many students in the class can be expected to receive a score between 82 and 90? Express answer to the nearest student.
Answer:
mean plus one standard deviation = 81.2
mean plus two standard deviation = 90.1The range between 1 and 2 standard deviations is used and considered to be "close enough".
As read from the chart, the amount of the distribution between 1 and 2 standard deviations above the mean is 13.6%.
13.6% of 184 students = 25 students.
(to the nearest student)
Websites:
http://www.mathsisfun.com/data/standard-normal-distribution.html
http://mathworld.wolfram.com/NormalDistribution.html
http://stattrek.com/probability-distributions/normal.aspx
http://www.itl.nist.gov/div898/handbook/eda/section3/eda3661.htm
http://www.itl.nist.gov/div898/handbook/eda/section3/eda3661.htm
Professor Halen has 184 students in his college mathematics lecture class. The scores on the midterm exam are normally distributed with a mean of 72.3 and a standard deviation of 8.9. How many students in the class can be expected to receive a score between 82 and 90? Express answer to the nearest student.
Answer:
mean plus one standard deviation = 81.2
mean plus two standard deviation = 90.1The range between 1 and 2 standard deviations is used and considered to be "close enough".
As read from the chart, the amount of the distribution between 1 and 2 standard deviations above the mean is 13.6%.
13.6% of 184 students = 25 students.
(to the nearest student)
Websites:
http://www.mathsisfun.com/data/standard-normal-distribution.html
http://mathworld.wolfram.com/NormalDistribution.html
http://stattrek.com/probability-distributions/normal.aspx
http://www.itl.nist.gov/div898/handbook/eda/section3/eda3661.htm
http://www.itl.nist.gov/div898/handbook/eda/section3/eda3661.htm