Descriptive Sta...

For a series the information available is $$n=10$$, $$\displaystyle\sum x=60, \displaystyle\sum x^2=1000$$. The standard deviation is?

The standard deviation of $$15$$ terms is $$6$$ and each item is decreased by $$1$$. Then the standard deviation of new data is?

For r.v. X whose p.m.f. is

The standard deviation of $$1, 2, 3, 4, 5, 6, 7$$ is?

If the variance of the data 2,4,5,6,8,17 is 23,33, then variance of 5,11,14,17,23,50 is ________________.

$$\sum _{ i=1 }^{ 10 }{ { \left( { X }_{ i }-10 \right)  }^{ 2 }=2000 } \sum _{ i=1 }^{ 10 }{ { X }_{ i }-10 } =100$$ then the standard deviation of data set $${X}_{i}$$.

In an experiment with $$10$$ observations on $$x,\displaystyle \sum { x=60, } \displaystyle \sum { { x }^{ 2 } } =1000$$ one observation that was $$20$$ was found to be wrong and was replaced by the correct value $$30$$ then the correct variance is 

Find the standard deviation of 10 observation 111, 211, 311,.......,1011.

The mean and standard deviation of $$1,2,3,4,5,6$$ are 

The average marks of 10 students in a class is 60 with standard deviation 4 while the average marks of other 10 students is 40 with standard deviation 6. If all the 20 students are taken together, their standard deviation will be