Have I approached this question correctly?
50 people in a call centre. Th chance of a person being off is 0.02
what is the probability of no more than 2 people being off
3 outcomes match this, everyone in, 1 off & 2 off
everyone in
0.98 to the power 50 = .3642
1 off
0.98 to the power of 49 * 0.2 * 50 = .3716 (the 50 comes from 50 C 1)
2 off
0.98 to the power of 48 * 0.2 to the power of 2 * 1225 = .1858 (the 1225 comes from 50 C 2)
so the answer to the q would be .3642 + .3716 + .1858 = 0.9216
I think I have the right answer but it’s been a while since I did my Mathematics A Level.
You should be using 0.02, not 0.2.
Doh! Thats a typo, the answers given did use .02
You are assuming that the probabilities are independent. This is a very strong assumption and is highly unlikely to be true.
The question statd the chance of anyone being off was 1 in 50. Nothing was said about subsequent absentees chancs bing dependant on the prior absentees, so yes I have calculatd assuming independent probabilities of absence
The calculations are correct assuming independence of absentee employees. Whether that’s a reasonable assumption is another question.
If this is an “artificial” question (like on a test or homework), it almost certainly is, since otherwise there’s not enough information given. In the real world, though…