A factory makes both rods and copper tubes, with diameters expressed in
millimetres. Due to variations in the manufacturing process, it is known
that the internal diameter of a copper tube is N (22, 0.4²), while the diameter
of a rod is N (21.5, 0.3²).
• Find the proportion of tubes with an internal diameter less than
• Find the proportion of rods with a diameter greater than 21.4mm
• Find the proportion of rods with a diameter between 21.6mm and
• A rod and tube are chosen at random. Find the probability that the
rod will not pass through the tube.
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- Thread Starter
Last edited by louiserogers; 01-04-2011 at 02:05.
- 01-04-2011 02:02
- 01-04-2011 02:24
1) tube: T~N (22, 0.4²)
So you want P(T < 21.4)
Which part did you want help with?