Answer:
a) 0.30854
b) 0.21186
c) 0.23468
Step-by-step explanation:
Mario's Pizza delivers pizzas within a 10-mile radius of the restaurant. Their delivery times are Normally distributed with a mean delivery time of 30 minutes and a standard deviation of 10 minutes.
We solve using z score formula.
z = (x-μ)/σ, where
x is the raw score
μ is the population mean
σ is the population standard deviation.
Find the probability that a randomly selected customer will have to wait
a) less than 25 minutes
for x < 25 minutes
z = 25 - 30/10
z = -0.5
Probability value from Z-Table:
P(x<25) = 0.30854
b) more than 38 minutes
For x > 38 minutes
z = 38 - 30/10
z = 0.8
Probability value from Z-Table:
P(x<38) = 0.78814
P(x>38) = 1 - P(x<38) = 0.21186
c) between 26 and 32 minutes
For x = 26 minutes
z = 26 - 30/10
z = -0.4
Probability value from Z-Table:
P(x = 26) = 0.34458
For x = 32 minutes
z = 32 - 30/10
z = 0.2
Probability value from Z-Table:
P(x = 32) = 0.57926
The probability that a randomly selected customer will have to wait between 26 and 32 minutes is calculated as:
P(x = 32) - P(x = 26)
= 0.57926 - 0.34458
= 0.23468
