Mathematics 9709 · AS & A Level · Sampling and estimation
Sampling and estimation — practice question
Maroulla’s calculator can produce random numbers from $0.000$ up to $0.999$, inclusive, to 3 significant figures. She intends to use it to select a sample of members from the 851 members in her health club. She labels the members from 1 to 851. She then enters some random numbers on her calculator. Each random number is multiplied by $851$ and rounded up to the next whole number, giving the number of a member in the sample. This is called a ‘member number’.
(a)[1]
Maroulla’s first random number is $0.401$. Determine the member number that this random number gives.
(b(i))[1]
Find every possible random number, correct to 3 decimal places, that would result in a member number of $680$.
(b(ii))[1]
Find every possible random number, correct to 3 decimal places, that would result in a member number of $850$.
(c)[1]
Explain briefly how your answers to part (b) show that Maroulla’s method does not give a random sample.
Worked solution & mark scheme
This 4-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Member number $342$” …