- The geometric mean of three
numbers was computed as 6. It was
subsequently found that in this
computation, a number 8 was wrongly
read as 12. What is the correct
geometric mean?
(a) 4 (b) √^ (c) 2√^ (d) None of
these
- The variance of the first n natural
number is:
(a) (^
(^) )
(b)
( )
(c)
( )
(d)
( )
- The arithmetic mean of 100
numbers was computed as 89.05. It
was later found that two numbers 92
and 83 have been misread as 192 and
33 respectively. What is the correct
arithmetic mean of these numbers?
(a) 88.55 (b) 87.55 (c) 89.55 (d)
Cannot be calculated from the given
data - A class consists of 3 sections A, B
and C with 35, 35 and 30 students
respectively. The arithmetic means of
the marks secured by student of
sections A and B, who appeared for a
test of 100 marks are 74 and 70
respectively. The arithmetic of mean of
the marks secured by students of
section C, who appeared for a test in
the same subject which carried 75
marks is 51. What is the average
percentage of marks secured by all the
100 students of the three sections?
(a) 70 (b) 70.8 (c) 65 (d) 67.5
22. If n= 20, ̅= 50 and ∑ = 84000,
then the variance is equal to:
(a) 1500 (b) 1700 (c) 1750 (d) 1800
23. The marks of the students of a class
who appeared for a test in English are
represented in the following frequency
table.
Class
interv
al1
-
1
0
1
1 -
2
0
2
1 -
3
0
3
1 -
4
0
4
1 -
5
0
5
1 -
6
0
Frequ
ency9 2
2
- 2
0
1
2
8 100
(total
freque
ncy)What is/are the modal class (es)?
(a) 10.5-20.5 only (b) 20.5-30.5 only
(c) 10.5-20.5 and 20.5-30.5 (d) There
is no modal class- If the median of x/5, x/4, x/2, x and
x/3, where x>0, is 8 then the value of x
is equal to:
(a) 26 (b) 24 (c) 20 (d) 32 - Following table gives the mean and
variance of monthly demand for four
products A, B, C and D in a super
market:
Product A B C D
Mean
Demand
Variance60
12
90
25
80
36
120
16
For which product the demand is
consistent?