7 The weight of adult female giraffes has a normal distribution with mean 830 kg and standard deviation 120 kg .
- There are 430 adult female giraffes in a particular game reserve. Find the number of these adult female giraffes which can be expected to weigh less than 700 kg .
- Given that \(90 \%\) of adult female giraffes weigh between \(( 830 - w ) \mathrm { kg }\) and \(( 830 + w ) \mathrm { kg }\), find the value of \(w\).
The weight of adult male giraffes has a normal distribution with mean 1190 kg and standard deviation \(\sigma \mathrm { kg }\). - Given that \(83.4 \%\) of adult male giraffes weigh more than 950 kg , find the value of \(\sigma\).