SOLUTION: The pizza delivery department receives 75% brand pizza orders. Find the probability that among 100 received orders there will be (a) 72 brand pizza orders; (b) from 70 to 78 brand

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Question 1143095: The pizza delivery department receives 75% brand pizza orders. Find the probability that among 100 received orders there will be (a) 72 brand pizza orders; (b) from 70 to 78 brand pizza orders. (c) Find the most probable number of brand pizza orders.
Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
The most probable number is 100*0.75 or 75
for 72, it is 100C72*0.75^72*0.25^28=0.0701
use normal approximation for 70 to 78 but could use the above approach 9 times and add.
mean is 75
variance is 75*.25=18.75
sd is sqrt (V)=4.33
for 70, use correction factor of 69.5
z=(69.5-75)/4.33 or -1.27
and
z=(78.5-75)/4.33=+0.81
that probability is 0.6890