JEE Main Questions
The mean and variance of eight observations are 9 and 9.25, respectively. If six of the observations are 6, 7, 10, 12, 12 and 13, find the remaining two observations.
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The following table gives the distribution of income of 100 families in a village. Calculate the standard deviation:
Income Rs., 0-1000, 1000-2000, 2000-3000, 3000-4000, 4000-5000, 5000-6000
No. of Families, 18, 26, 30, 12, 10, 4
Find the standard deviation for the following data:
, 3, 8, 13, 18, 23
, 7, 10, 15, 10, 6
, 2, 3, 4, 5, 6, 7, 7
, 4, 9, 16, 14, 11, 6, 6
Let x1,x2,……,xn be values taken by a variable Xandy1,y2,……….,yn be the values taken by a variable Y such thatyi=axi+b,i=1,2,,n˙ Then, (a)Var(Y)=a2Var(X) (b) Var(X)=a2Var(Y)
(c) Var(X)=Var(X)+b (d) none of these
A class teacher has the following absentee record of 40 students of a class for the whole term. Find the mean number of days a student was absent.
Find the mean deviation about the mean for the data 4,7,8,9,10,12,13,17
The mean of 100 numbers observations is 50 and their standards deviation is 5. The sum of all squares of all the observations is (a)50,000 (b) 250,000 (c) 252500 (d) 255000
The blood groups of 30 students of Class VIII are recorded as follows:A,B,O,O,AB,O,A,O,B,A,O,B,A,O,O,A,AB,O,A,A,O,O,AB,B,A,O,B,A,B,O.Represent this data in the form of a frequency distribution table. Which is the most common, and which is the rarest, blood group among these students?
The following table gives the distribution of the life time of 400 neon lamps: