For the following data, mean of x is found to be 7.3. The missing frequency is x: 5 6 7 8 9 f : 4 6 12 - 8
10
9
8
7
The harmonic mean of the numbers 2, 3, 4 is _______.
3
( 24 )1/3
36/13
13/36
The central value of the set of observations is called
Mean
Median
Mode
G.M
The mean of the squares of first n natural numbers is
1/8 n ( n + 1 )
1/6 n ( 2n +1 )
1/6 ( n + 1 ) ( 2n + 1 )
G.M of 4, 5, 20, 25 is
11
The AM of the series 1, 2, 4, 8 ..... 2n is
If the regression coefficients are o.8 and 0.2, then the value of co - efficients of correlation is
0.16
0.4
0.04
None of these
The range of following set of observations : 2, 3, 5, 9, 8, 7, 6, 5, 7, 4, 3, is
5.5
6
The mean age of 50 persons was found to be 32 years. Later it was detected that the age 28 was wrongly noted as 35, the age 57 was wrongly noted as 30 and the age 60 was wrongly noted as 32. Then the correct mean age is
28
33
31
32.4
If x and y are two variables such that
1/2
- 1/2
1/4
- 1/4
