Statistics

If the variance of the frequency distribution array|c|c|c|c|c|c|c| x & c & 2c & 3c & 4c & 5c & 6c \ f & 2 & 1 & 1 & 1 & 1 & 1 \ array is 160, then the value of c N is

1. 5
2. 8
3. 6
4. 7

Let a, b, c N and a < b < c. Let the mean, the mean deviation about the mean and the variance of the 5 observations 9, 25, a, b, c be 18, 4 and 1365, respectively. Then 2a + b - c is equal to

The mean and standard deviation of 20 observations are found to be 10 and 2, respectively. On rechecking, it was found that an observation by mistake was taken 8 instead of 12. The correct standard deviation is

1. 1.94
2. 3.96
3. 3.86
4. 1.8

Let , R. Let the mean and the variance of 6 observations -3, 4, 7,-6, , be 2 and 23, respectively. The mean deviation about the mean of these 6 observations is :

1. 163
2. 113
3. 143
4. 133

Let the median and the mean deviation about the median of 7 observations 170, 125, 230, 190, 210, a, b be 170 and 2057 respectively. Then the mean deviation about the mean of these 7 observations is :

1. 31
2. 28
3. 30
4. 32

Consider 10 observations x1, x2, , x10 such that i=110 (xi- )=2 and i=110 (xi- )2=40, where , are positive integers. Let the mean and the variance of the observations be 65 and 8425 respectively. Then is equal to :

1. 2
2. 1
3. 52
4. 32

Let the mean and the variance of 6 observations a, b, 68, 44, 48, 60 be 55 and 194, respectively. If a>b, then a+3b is

1. 180
2. 210
3. 190
4. 200

Let M denote the median of the following frequency distribution [figure] Then 20M is equal to :

1. 104
2. 52
3. 208
4. 416

The variance 2 of the data [figure] is .

If the mean and variance of the data 65,68,58,44,48,45,60, , ,60 where > , are 56 and 66.2 respectively, then 2+ 2 is equal to .