Question 659927
<pre>
Some books say:

Calculate np and n(1 - p) and if both are
greater than 5, the approximation is good.

np > 5 and n(1 - p) > 5

np = 20(0.76) = 15.2

n(1 =- p) = 20(1 - 0.76) = 4.8

The second one is not > 5 so it would not be a good approximation.
 
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Other books say:

Calculate np(1 - p) and if this is >= 10 then the approximation is good.

np(1 - p) = (20)(0.76)(1 - 0.76) = 3.648

That is not greater than or equal to 10

So the normal approximation would not be good in either case.

Edwin</pre>