A barbershop requires appointments for perms and hair cuts. Ten percent of those making appointments cancel or simply fail to show up. Next week's appointment calendar has 64 appointments. Let x be the number of missed appointments out of the 64. The probability that more than 3 cancellations and/or no-shows will occur during the next week is:

The probability that more than 3 cancellations and/or no-shows will occur during the next week is: 0.8937

This involves binomial probability distribution with the formula;

P(X = x) = ⁿCₓ × pˣ × q⁽ⁿ ⁻ ˣ⁾

We are given;

p = 10% = 0.1

n = 64

q = 1 - p = 1 - 0.1

q = 0.9

We want to find the probability that more than 3 cancellations and/or no-shows will occur during the next week is given by;

P(X > 3) = 1 - (P(X = 0) + P(X = 1) + P(X = 2) + P(X =3))

From online binomial probability calculator;

P(0) = 0.0012

P(1) = 0.0084

P(2) = 0.0293

P(3) = 0.0674

Thus;

P(X > 3) = 1 - (0.0012 + 0.0084 + 0.0293 + 0.0674 )

P(X > 3) = 1 - 0.1063

P(X > 3) = 0.8937

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0.8937

Step-by-step explanation:

This is a case of binomial probability with n = 64, p = 0.10 and x = 3.  This means that the probability of a cancellation is 10%.  Here, we can find the probability that more than 3 cancellations or no shows will occur by finding binompdf(64,0.10, 0) + binompdf(64,0.10, 1) + binompdf(64,0.10, 2) + binompdf(64,0.10, 3) and then subtracting this sum from 1.000.  

We get:    0.0012 + 0.0084 + 0.0293 + 0.0674 = sum = 0.1063

Then the desired probability is 1.0000 - 0.1063 = 0.8937