The tensile strengths of alloy cables produced by industrial extrusion machines are normally distributed. Machine XXX produces cables with a mean tensile strength of 450 MPa and a standard deviation of 24 MPa.
Find the probability that a cable from Machine XXX has a tensile strength of less than 414 MPa.
In a production batch of 600 cables from Machine XXX, determine the expected number of cables having a tensile strength of less than 414 MPa.
Another machine, Machine YYY, produces cables with a mean tensile strength of 465 MPa. It is known that 12%12\%12% of these cables have a tensile strength of less than 435.6 MPa.
Calculate the standard deviation of the tensile strengths of cables from Machine YYY.
Both machines operate at the same utility cost per cable.
State which machine you would recommend for procurement. Give reasons for your answer.
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.
