(i)[3]
It is discovered that $13\%$ of seeds take more than $136$ hours to germinate. Determine the value of $\sigma$.
(ii)[4]
$170$ seeds are sown. Find the expected number of seeds with germination times between $131$ and $141$ hours.
Mathematics 9709 · AS & A Level · Continuous random variables
Continuous random variables — practice question
Under these conditions, the germination time of cucumber seeds follows a normal distribution with mean $125$ hours and standard deviation $\sigma$ hours.
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