5 . The following box-and-whisker diagram shows the number of hours spent shopping online of a group of 20 boys and 40 girls in a particular month .
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( a ) Let D be the inter-quartile range . Write down the range of values of D .
[ 1 ]
The group of 20 boys spent a total of 120 hours of online shopping .
( b ) Write down the mean number of hours that the boys spent shopping online in that month .
[ 1 ]
The mean and the standard deviation in the number of hours that the girls spent shopping online are 10.5 hours and 2 hours respectively . It is also given that in the next month , all girls spent 1.5 more hours in online shopping .
( c ) |
( i ) |
Find the mean number of hours that the girls spent shopping |
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online in the next month . |
( ii ) Find the variance in the number of hours that the girls spent shopping online in the next month .
[ 5 ]
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