The random variable XXX is normally distributed with unknown mean μ\muμ and known variance σ2\sigma^2σ2. A random sample of nnn observations of XXX produced a 95%95\%95% confidence interval for μ\muμ of (12.42,12.85)(12.42, 12.85)(12.42,12.85).
Show that the standard error used to find this confidence interval is 0.1100.1100.110 to 333 significant figures.
Using the same random sample,
find a 98%98\%98% confidence interval for μ\muμ. Give your answers to 333 decimal places.
The r%r\%r% confidence interval using the same random sample has a width of 0.500.500.50.
Calculate the value of rrr.
Practise Edexcel A Level Maths The Normal Distribution with exam-style questions for A Level Maths. 439 questions, matched to the Edexcel A Level Maths (9MA0) specification and written in Paper 1, Paper 2 and Paper 3 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.
