7 . The height H m of peach trees in a garden are normally distributed with mean 2.85 m and standard deviation 0.19 m .
( a ) Write down the probability that the height of a randomly chosen peach tree is
( i ) within 1 standard deviation of the mean ;
( ii ) within 2 standard deviation of the mean . [ 2 ]
( b ) Find the probability that the height of a randomly chosen peach tree is shorter than 2.82 m .
( c ) Find the value of r if 28 % of the peach trees are taller than r m .
[ 2 ]
[ 2 ]
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