The amount W W\,W ml placed in a bottle is normally distributed with mean 500 ml. It is known that P(W>504)=0.30P(W>504)=0.30P(W>504)=0.30.
Find the standard deviation of WWW.
Find P(W<490)P(W<490)P(W<490).
Comment on whether the model permits physically impossible values.
328 exam-style questions on WJEC A Level Maths 4.2 Statistical distributions (A-level only), covering 4.2.1 Statistical distributions (A-level only), 4.2.2 Statistical distributions (A-level only), and 4.2.3 Statistical distributions (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.