If 10 is the mean of a set of 7 observation and 5 is the mean of a st of 3 observations, then the mean of the combined set is
15
10
8.5
7.5
The mean of first n - natural number is
n/2
The variance of first n natural numbers is
The heights ( in cm ) of the 15 students of a class are 152, 145, 156, 149, 151, 159, 148, 160, 153, 154, 150, 143, 155,
157, 161 cm. The median of height of the student is
152 cm
149 cm
153 cm
150 cm
The marks obtained in chemistry by the 15 students of class XI B are
20, 15, 10, 20 27, 28, 27, 10, 20, 30 35, 40, 41, 41, 20 then the value of mode is
20
27
41
If in a moderately skewed distribution the value of mode and mean are 6 λ and 9λ respectively, then the value of the median is ______.
8 λ
7 λ
6 λ
5 λ
The mean of 9 observation is 100 and that of 6 observations is 80, then the combined mean of all 15 observation is
100
92
90
80
If 96 is the variance of the scores of a batsman in matches played by him. Then the standard deviation is
6.87
9.79
9.98
10.9
The mean of 5 numbers is 18. If one number is excluded, their mean becomes 16, then the excluded number is
18
25
26
30
The median of the observations 2, 30, 12, 25, 20, 8, 10, 4, 15, Is
12