These questions must be completed using the BINOMDIST formul

*These questions must be completed using the BINOMDIST formula*

A dentist sees about fifteen new patients per month (the rest of the patients are repeats). She knows that on average, over the past year, about half of her patients have needed at least one filling on their first visit.

a) What is the probability that she will see ten patients or more out of fifteen who need fillings?
b) What is the probability that she will see five or fewer patients that need fillings?
c) What is the probability that she will see between seven and ten new patients who need fillings?

*Please do not screen shout you reply

Solution

a)

As the cumulative binomdist function accumulates \"at most\" x successes, then

P(at least 10) is

=1 - BINOMDIST(9, 15, 0.5, 1)

P(at least 10) = 0.150878906 [answer]

******************

b)

P(at most 5):

=BINOMDIST(5, 15, 0.5, 1)

=0.150878906 [ANSWER]

************************

C)

P(between 7 and 10):

=BINOMDIST(10, 15, 0.5, 1) - BINOMDIST(6, 15, 0.5, 1)

=0.637145996 [ANSWER]