Statistics practice problems:
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Practice problems in finding the mean.
a)
|
Class Interval |
5 – 15 |
15 – 25 |
25 – 35 |
35 – 45 |
45 – 55 |
55 – 65 |
|
Frequency |
3 |
6 |
12 |
8 |
4 |
2 |
b)
|
x |
7 |
12 |
15 |
33 |
45 |
51 |
|
f |
5 |
4 |
9 |
12 |
10 |
15 |
c) Find the mean height for the data given here.
|
Height (in cm) |
32.5 – 37.5 |
37.5 – 42.5 |
42.5 – 47.5 |
47.5 – 52. |
|
Frequency |
39 |
9 |
8 |
6 |
d) Find the value of P if the mean of the following data is 16.6
|
X |
8 |
12 |
15 |
P |
20 |
25 |
30 |
|
f |
12 |
16 |
20 |
24 |
16 |
8 |
4 |
|
Age in years |
25 – 30 |
30 – 35 |
35 -40 |
40 – 45 |
45 -50 |
50 – 55 |
|
No. of workers |
30 |
23 |
20 |
14 |
10 |
3 |
Practice problems in Median
1. Find the median of the following data:
|
X |
5 |
7 |
9 |
12 |
14 |
17 |
19 |
21 |
|
F |
6 |
5 |
3 |
6 |
5 |
3 |
2 |
4 |
2. Find the median :
|
Marks |
10 -20 |
20 – 30 |
30- 40 |
40 – 50 |
50 – 60 |
60 – 70 |
70 – 80 |
|
No. of students |
12 |
30 |
34 |
65 |
45 |
25 |
18 |
Practice problems in Mode
1. Find the mode of the following distribution of marks of 40 students in a Mathematics test.
(The marks are out of a maximum of 25)
|
Marks: |
0 – 5 |
5 – 10 |
10 – 15 |
15 – 20 |
20 – 25 |
|
No. of students |
1 |
9 |
15 |
10 |
5 |
2. The following table gives the distribution of height (in cm) of 200 children. Find the modal height.
|
Height |
95- 105 |
105 – 115 |
115 – 125 |
125 – 135 |
135 – 145 |
|
No. of Children |
19 |
23 |
36 |
70 |
52 |