CHAPTER 6
Elementary Statistics
16
=
2
+
5
4
5
0
=
2
+
5
9
5
5
MODE
2
=
=
¡
¡
2
SHIFT
;
’
1
0
M+
5
7
SHIFT
;
’
1
1
M+
5
The weight distribution of 100 students is given in the table. Calculate an
estimate of the mean and the standard deviation for this distribution.
Weight
(kg)
Frequency
50-54 10
55-59 11
60-64 22
65-69 29
70-74 12
75-79 16
OPERATION
1
. First, determine the mid-point for all class intervals.
Then,
2
. Use similar operations as in step 1 to find the rest of the mid-points, we will get the result
as below.
3
. Now enter
SD (
standard deviation
)
mode. Press
4
. Input all data obtained in step 2.
Weight
(kg)
Mid-point Frequency
50-54 52 10
55-59 57 11
60-64 62 22
65-69 67 29
70-74 72 12
75-79 77 16
Example 1
50+54
104
Ans
¡
2
52
55+59
114
Ans
¡
2
57
SD D
0
n=
SD
D
10
n=
SD
D
21