The following table gives the distribution of the life time of 400 neon lamps :
1500 - 2000
14
2000 - 2500
56
2500 - 3000
60
3000 - 3500
86
3500 - 4000
74
4000 - 4500
62
4500 - 5000
48
Find the median life time of a lamp.
100 surnames were randomly picked up from a local telephone directory and the frequency distribution of the number of letters in the English alphabets in the surnames was obtained as follows:
Number of letters
1 - 4
4 - 7
7 - 10
10 - 13
13 - 16
16 - 19
Number of surnames
6
30
40
16
4
Determine the median number of letters in the surnames. Find the mean number of letters in the surnames? Also, find the modal size of the surnames.
The distribution below gives the weights of 30 students of a class. Find the median weight of the students.
40 - 45
45 - 50
50 - 55
65 - 60
70- 65
65 - 70
70 - 75
2
3
8
A student noted the number of cars passing through a spot on a road for 100 periods each of 3 minutes and summarised it in the table given below. Find the mode of the data :
The given distribution shows the number of runs scored by some top batsmen of the world in one-day international cricket matches.
3000 - 4000
4000 - 5000
18
5000 - 6000
9
6000 - 7000
7
7000 - 8000
8000 - 9000
9000 - 10000
1
10000 - 11000
Find the mode of the data.
The following distribution gives the state-wise teacher-student ratio in higher secondary schools of India. Find the mode and mean of this data. Interpret the two measures.
The following data gives the distribution of total monthly household expenditure of 200 families of a village. Find the modal monthly expenditure of the families. Also, find the mean monthly expenditure :
Expenditure (in Rs)
Number of families
1000 - 1500
24
33
28
22
Lifetimes (in hours)
0 - 20
20 - 40
40 - 60
60 - 80
80 - 100
100 - 120
Frequency
10
35
52
61
29
The following table shows the ages of tha year:
Age (in years)
5 - 15
15 - 25
25 - 35
35 - 45
45 - 55
55 - 65
Number of patients
11
21
23
5
Find the mode and the mean of the data given above. Compare and interpret the two measures of central tendency.
Prove the following identities, where the angles involved are acute angles for which the expressions are defined:\(\frac{(\text{1 + tan² A})}{(\text{1 + cot² A})} = (\frac{\text{1 - tan A }}{\text{ 1 - cot A}})^²= \text{tan² A}\)