Consider a set S given as {11,22,33,44,55,66,77,88,99} . If each element of the data set is multiplied by -7 then by what factors will the Mean,Variance and Standard Deviation respectively change ?  Choose the correct choice from the following.
A) -7,-7,-7	B) -7,7,7	C) 1,1,1	D) -7,49,7	E) 7,7,49
Mean: If all values are multiplied by -7 then their sum will also be multiplied by -7 so Mean will also get -7   Variance:   Variance is equal to (Sum of (Square of (the difference between mean and individual values))/Total number of values   When we multiply all the values by -7 then the difference between the mean and the individual values also gets multiplied by -7 and the square of that difference becomes 49. So, the variance gets multiplied by a factor of 49   SD:   Standard Deviation is the square root of variance so sqrt(49)=7. So SD gets multiplied by a factor of 7.   So, answer will be -7,49,7.
<result>D</result>
Consider a set S given as {11,22,33,44,55,66,77,88,99} . If each element of the data set is multiplied by -7 then by what factors will the Mean,Variance and Standard Deviation respectively change ?