One-hour carbon monoxide concentrations in air samples from a large city average 12 ppm (parts per million) with standard deviation 9 ppm. Required:
a. Do you think that carbon monoxide concentrations in air samples from this city are normally distributed.
b. Find the probability that the average concentration in 100 randomly selected samples will exceed 14 ppm.

0.0132

Step-by-step explanation:

No

Carbon monoxide concentrations sample in air from a large city are not normally distributed. This is often so because of the time of the day and that of the night. There exists different concentrations during the day, with respect to during the night. The companies and factories work during the day, so does most vehicles. This means that there tend to be a higher concentration during the day, than there will be during the night.

b)

Assuming that Y' is approximately normal, we can say that

P(Y' > 14) = P(Z > [√100(14 - 12)/9]) and this is equal to

P(Z > 2.22) = 0.013

$7 + $0.20p = $5 + $0.30p

Step-by-step explanation:

UPS charges $7 for the first pound and $0.20 for each additional pound.

FedEx charges $5 for the first pound and $0.30 for each additional pound.

Let's take the number of  additional pounds that will make UPS and FedEx cost the same to be p.

$7 + $0.20p = $5 + $0.30p

$7 - $5 = $0.30p - $0.20p

$2 = $0.10p

p = = 20 additional pounds