EASY
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The coefficient of variation (C.V.) and the mean of a distribution are respectively 75 and 44. Then the standard deviation of the distribution is

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Important Questions on Statistics

MEDIUM
The mean and variance of a binomial distribution are 8 and 4 respectively, then P( X=1 ) is equal to
EASY
The mean of a distribution is 14 and the standard deviation is 5. What is the value of the coefficient of variation?
EASY
A random variable XB(n, p). If values of mean and variance of X are 18 and 12 respectively then total number of possible values of X are
EASY
Find the least positive value of k, if the range of 15,14, k, 25,30,35 is 23.
MEDIUM
Coefficient of variation of two distributions are 60 and 70 and their standard deviations are 21 and 16 respectively. Then their AM's are
MEDIUM
In a binomial distribution the mean is 15 and variance is 10. Then parameter n is
HARD
A box contains 15 green and 10 yellow balls. If 10 balls are randomly drawn, one-by-one, with replacement, then the variance of the number of green balls drawn is:
EASY
If 65 is the range of the ungrouped data 50, 70, 60, B, 20, 40 then the absolute difference of the possible values of B is
MEDIUM
Coefficient of variation of two distributions are 60 and 70, and their standard deviation are 21 and 16, respectively. What are their arithmetic means?
MEDIUM
If the numbers are 5,1,8,7,2, then the coefficient of variation is
EASY
The range of the observations 20,28,40,12,30,15,50 is _____
MEDIUM
The means of two groups of observations A and B are x, y respectively and their standard deviations are respectively 2 and 3. In order that the group A is to be more consistent than the group B, yx<
MEDIUM
The variance of 20 observations is 5. If each observation is multiplied by 2, then the variance of the resulting observation is
EASY
The mean and variance of a binomial variable X are 2 and 1 respectively. The probability that X takes values greater than 1, is
EASY
If 3% of the electric bulbs manufactured by a company are defective, the probability that in a sample of 100 bulbs exactly 5 bulbs are defective is
EASY
If the mean of a data x¯ is 10 and if all the observations are multiplied by 2, then the mean of new data is
EASY
For a given distribution the arithmetic mean is 15 and the standard deviation is 9 then the coefficient of variation is equal to
MEDIUM

The marks obtained by students A and B in 3 examinations are given below

Marks of A 30 20 40
Marks of B 70 0 5

The ratio of the coefficient of variation of marks of A and the coefficient of variation of marks of B is

MEDIUM
Coefficient of variation of two distributions are 50 and 60 and their arithmetic means are 30 and 25, respectively. Difference of their standard deviation is