| X | 1 | 2 | 3 |
| P(X=x) | 0.3 | 0.4 | 0.3 |
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Qn #1613
00:00
A random variable X has the distribution law as given below:
The variance of the distribution is
Qn #1590
If $\overline{X_1}$ and $\overline{X_2}$ are the means of two distributions such that
$\overline{X_1} < \overline{X_2}$ and $\overline{X}$ is the mean of the combined
distribution, then
Qn #1529
Qn #1527
In a group of 200 students, the mean and the standard deviation of scores were found to be 40 and 15,
respectively. Later on it was found that the two scores 43 and 35 were misread as 34 and 53, respectively. The corrected mean of scores is:
Qn #1416
If the mean deviation of the numbers 1, 1 + d, 1 + 2d, ....., 1 + 100d from their mean is 255, then
the value of d is
Qn #1240
isQn #1161
Qn #1073
Qn #1059
Let $X_i, i = 1,2,.. , n$ be n observations and $w_i = px_i +k, i = 1,2,
,n$ where p and k are constants. If the mean of $x_i 's$ is 48 and the standard deviation is 12, whereas the mean of $w_i 's$ is 55 and the standard deviation is 15, then the value of p and k should be
Qn #1040
The mean of 5 observation is 5 and their variance is 12.4. If three of the observations are 1,2 and 6; then the mean deviation from the mean of the data is:
Qn #1004
Standard deviation for the following distribution is
| Size of item | 6 | 7 | 8 | 9 | 10 | 11 | 12 |
| Frequency | 3 | 6 | 9 | 13 | 8 | 5 | 4 |
Qn #1003
A, B, C are three sets of values of x:
A: 2,3,7,1,3,2,3
B: 7,5,9,12,5,3,8
C: 4,4,11,7,2,3,4
Select the correct statement among the following:
Qn #876
Consider the following frequency distribution table.
| Class Interval | 10-20 | 20-30 | 30-40 | 40-50 | 50-60 | 60-70 | 70-80 |
| Frequency | 180 | $f_1$ | 34 | 180 | 136 | $f_2$ | 50 |
If the total frequency is 686 and the median is 42.6, then the value of $f_1$;and $f_2$ are
Qn #859
If a variable takes values 0, 1, 2,…, 50 with frequencies $1,\, {{50}}_{{{C}}_1},{{50}}_{{{C}}_2},\ldots..,{{50}}_{{{C}}_{50}}$, then the AM is
Qn #840
The standard deviation of 20 numbers is 30. If each of the numbers is increased by 4, then the new standard deviation will be
Qn #749
Consider the following frequency distribution table.
| Class interval | 10-20 | 20-30 | 30-40 | 40-50 | 50-60 | 60-70 | 70-80 |
| Frequency | 180 | $f_1$ | 34 | 180 | 136 | $f_2$ | 50 |
If the total frequency is 685 & median is 42.6 then the values of $f_1$ and $f_2$ are
Qn #748
For a group of 100 candidates, the mean and standard deviation of scores were found to be 40 and 15
respectively. Later on, it was found that the scores 25 and 35 were misread as 52 and 53 respectively. Then the
corrected mean and standard deviation corresponding to the corrected figures are
Qn #745
The mean of 5 observation is 5 and their variance is 12.4. If three of the observations are 1, 2 and 6; then the mean deviation from the mean of the data is:
Qn #627
It is given that the mean, median and mode of a data set is $1, 3^x$ and $9^x$ respectively. The possible values of the mode is
Qn #591
Given a set A with median $m_1 = 2$ and set B with median $m_2 = 4$
What can we say about the median of the combined set?
Qn #576
In
a reality show, two judges independently provided marks base do the performance
of the participants. If the marks provided by the second judge are given by Y =
10.5 + 2x, where X is the marks provided by the first judge. If the variance of
the marks provided by the second judge is 100, then the variance of the marks provided
by the first judge is: