Questions for practice
Class 11
Board –CBSE
Pankaj Bhanwani #9899971997
Topic – Measures of Central Tendency – Mean, median and mode
Q1 Find out median
|
Serial Number
|
Number of households
|
|
1
|
2
|
|
2
|
4
|
|
3
|
10
|
|
4
|
8
|
|
5
|
15
|
|
6
|
20
|
|
7
|
12
|
|
8
|
25
|
|
9
|
30
|
Answer -20
Q2 List of electric lamps is given in the following table.
Calculate the median and mode by grouping method
|
Life in hours
|
Number of lamps
|
|
Below 400
|
4
|
|
400-800
|
12
|
|
800-1200
|
40
|
|
1200-1600
|
41
|
|
2000-2400
|
13
|
|
2400-2800
|
9
|
|
Above 2800
|
4
|
Answer Median -1385.6
Mode -1226.66
Q3 Calculate mean of the following
|
Marks
|
Number of students
|
|
Less than 10
|
4
|
|
Less than 20
|
10
|
|
Less than 30
|
20
|
|
Less than 40
|
40
|
|
Less than 50
|
50
|
Answer 30.2
Q4 Find the missing frequency , if the mean is 29
|
Class Interval
|
F
|
|
0-10
|
5
|
|
10-20
|
F
|
|
20-30
|
12
|
|
30-40
|
18
|
|
40-50
|
5
|
|
50-60
|
3
|
|
Answer
|
7
|
Q5 The mean marks of 60 students in section A are 40 and mean marks
of 40 students in section B are 35 . Calculate the combined mean of all the
students of section A and B
Answer 38
Q6 Calculate mode by grouping method
|
Wages
|
No of person
|
|
125
|
3
|
|
175
|
8
|
|
225
|
21
|
|
275
|
6
|
|
325
|
4
|
|
375
|
2
|
|
Answer
|
225
|
Q7 The mean salary paid to 1000 workers of a factory was
found to be Rs180.4 Later on it was discovered that the wages of 2 workers were
wrongly taken as 297 and 165 instead of 197 and 185 .Find the correct mean
Answer 180.32
No comments:
Post a Comment