Automated security software monitors login attempts for potential breaches. For a specific category of low-risk attempts, the probability that the software fails to flag the attempt is 0.06. A security audit reviews these attempts in independent blocks of 50.
Determine the probability that a single block of 50 contains no more than 2 unflagged attempts.
The auditor evaluates 12 such independent blocks. Find the probability that fewer than 3 of these blocks contain at most 2 unflagged attempts.
Using a suitable approximation, estimate the probability that the total number of unflagged attempts across the 12 blocks is more than 45.
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.
