Section A ( 56 marks ) 1 . There are 15 items in a data set . The sum of the items is 300 .
( a ) Find the mean .
The variance of this data set is 9 . Each value in the set is multiplied by � 2 .
( b ) ( i ) Write down the value of the new mean .
( ii ) Find the value of the new variance .
[ 2 ]
( iii ) Hence , write down the value of the new standard deviation . [ 4 ]
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