Step-by-step explanation:
The grade of 10 students in statistics are 85, 70, 89, 84, 90, 92, 75, 81, 78 and 87. What is the range, mean and the standard deviation?
A. Range= 92- 70
answer = 22
B. Mean= sum of grades / # of students
Mean= 831/10
Mean= 83.1
C. Standard deviation = S square = the sum of x square - the sum of ( x square/ # of students)/ # of student - 1
which would work out like this:
number of students= 10
sum of x squared= 85*85=7225+70*70=4900+89*89=7921+84*84=7056+90*90=8100+92*92=8464+75*75=5625+81*81=6561+78*78=6084+87*87=7569.
Answer= 69,505
sum of x = 85+70+89+84+90+92+75+81+78+87
Ans = 831
(sum of x) squared / number of students=
831*831 =690561/10
answer= 69056.1
S square = the sum of x squared - the sum of ( x square/ # of students)/ # of student - 1
S square = 69505–69056.1/10–1
S square = 448.9/9
S square = 49.88
find the square root of 49.88
therefore standard deviation is:
Answer= 7.06