State the conditions under which the normal distribution may be used as an approximation to the binomial distribution X∼B(n,p)X \sim B(n, p)X∼B(n,p).
A production line produces "Bio-Fuse" electrical surge protectors. The company claims that 38% of these protectors are capable of absorbing a massive "Category 5" power spike.
Explain why the company would use a sample rather than testing every surge protector produced to verify this claim.
A safety board decides to investigate the claim by selecting a random sample of 400 surge protectors for rigorous spike testing.
State the hypotheses for a two-tailed test of the company's claim.
During the investigation, 172 of the 400 protectors successfully absorbed the "Category 5" spike. Using a normal approximation and a 5% level of significance, determine whether there is evidence to suggest that the company's claim is incorrect.
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.
