Statistics Test...

If $$\sum _{ i=1 }^{ 9 }{ ({ x }_{ i }-5)=9 } $$ and $$\sum _{ i=1 }^{ 9 }{ { { ( }x_{ i }-5 })^{ 2 }=45 }, $$ then the standard deviation of the 9 items $${ x }_{ 1 },{ x }_{ 2, }.........{ x }_{ 9 }$$ is

The standard deviation of $$50$$ values of a variable x is $$15$$; if each value of the variable is divided by $$(-3)$$; then the standard division of the new set of $$50$$ values of x will be

mean deviation from mean of the data 

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The variance of  $$20$$  observations is  $$5 .$$  If each observation is multiplied by  $$- 1$$  and added by  $$2 ,$$  then new variance is

for two data sets,each of size 5, the variances are given to be 4 and 5 andthe correspondings means are given to be 2 and 4 respectively. the variances of the combined data set is

The mean deviation about the mean of the following data is?

If mean deviation through median is 15 and median is 450, then coefficient of mean deviation is  

If $$\sum _{ i=1 }^{ 18 }{  } $$ $$(X_{i}-8)=9$$ and $$\sum _{ i=1 }^{ 18 }{  } $$$$(x_{i}-8)^{2}=45$$ , then the standard deviation of $$x_{1},x_{2},.....,x_{18}$$ is 

The standard deviation of the data 6, 5, 9, 13, 12, 8, 10 is