High school students in an International Baccalaureate IB pr

High school students in an International Baccalaureate (IB) program are placed in accelerated or advanced courses and must take IB examinations in each of six subject areas at the end of their junior or senior year. Students are scored on a scale of 1-7, with 1-2 being poor, 3 mediocre, 4 average, and 5-7 excellent. During its first year of operation at a high school, 16 juniors attempted the IB economics exam, with these results. Exam G rade Number of Students 6 5 4 3 6 2 2 Calculate the mean, x, and standard deviation, s, for these scores. (Round your answers to two decimal places.) x=475 s= 1.87 1.87

Solution

consider:

Thus,      
      

Variance = [Sum(x^2f) - Sum(xf)^2/Sum(f)]/[Sum(f)-1] =    2.066666667  

Standard deviation = sqrt(Variance) =    1.437590577 [ANSWER]

x	f	x f	x^2 f
7	1	7	49
6	6	36	216
5	2	10	50
4	2	8	32
3	5	15	45