The table shows the distribution of the number of hours per day spent in studying by 50 students.
Number of hours per day
4
5
6
7
8
9
10
11
Number of students
5
7
5
9
12
4
3
5
Calculate, correct to two decimal places,
the: (a) mean; (b) standard deviation.
Verified Correct Answer: .
Step-by-Step Mathematical Solution
x
f
fx
fx\(^2\)
4
5
20
80
5
7
35
175
6
5
30
180
7
9
63
441
8
12
96
768
9
4
36
324
10
3
30
300
11
5
55
605
£f = 50
£fx = 365
£fx\(^2\) = 2,873
(a) Mean(\(\overline{x}\)) = \(\frac{365}{50}\) = 7.30 (2 d.p.)
(b) Standard deviation = \sqrt(\(\frac{2873}{50}\)) - (7.3)\(^2\)
= \sqrt4.17
= 2.0421
= 2.04 (2 d.p.)
Source: Myschool Past Questions Archive (Record #61562)