The mean height of 25 male workers in a factory is 161cm and mean height of 35 female workers in the same factory is 158 cm. The combined mean height of 60 workers in the factory is
A159.25
B159.5
C159.75
D158.75
Question - 2
In an english learning classes, there are 8 men, 7 women and 5 children whose mean ages separately are respectively 24,20 and 6 yr. The mean age of English learning classes candidate is
A18.0
B18.1
C18.2
D18.3
Question - 3
If g1 and g2 are the geometric means of two series of n1 and n2 items. Then, the GM of the series obtained on combining is
The mean deviation and coefficient of mean deviation about the median from the data of weight (in kg) 54,50,40,42,51,45,47,55,57 is
A4.5, 0.0900
B4.78, 0.0956
C3.8, 0.0056
D4.96, 0.0946
Question - 5
Find the mean deviation about the mean of the following data.
Size
1
3
5
7
9
11
13
15
Frequency
3
3
4
14
7
4
3
4
A2.95
B3.24
C4
D2
Question - 6
The SD of a variate x is \(\sigma\). The SD of the variate \(ax+b\over c\), where a,b and c are constants is
A\(({a\over c})\sigma\)
B\(\begin{vmatrix} \frac { a }{ c } \end{vmatrix}\sigma \)
C\(({a^2\over C^2})\sigma\)
DNone of these
Question - 7
If the standard deviation of y1,y2,...yn is 3.5, then the standard deviation of -2y1-3,-2y2-3,...,-2yn-3 is
A-7
B9
C7
D2.45
Question - 8
The means of two samples of size 200 and 300 were found to be 25 and 10, respectively. Their standard deviations were 3 and 4, respectively. The variance of the combined sample of size 500 is
A64
B65.2
C67.2
D642
Question - 9
The sum of squares of deviations taken from mean 50 is 250. The coeficient of variation is
A10%
B40%
C50%
DNone of these
Question - 10
Which of the following statement regarding arithmetic mean is true?
AWhen observation is increased or decreased (by a constant), mean is also increased or decreased by a same constant
BWhen observation is increased (by a constant), mean will decreased by a same constant
CWhen observation is decreased (by a constant), mean will increased by a same constant
