Answer:
And we can find this probability with this difference:
And in order to find these probabilities using the normal standard distribution or excel and we got.
So we expect about 99.735% of values between $29 and $89
Step-by-step explanation:
Let X the random variable that represent the amount of Jens monthly phone of a population, and for this case we know the distribution for X is given by:
Where and
We are interested on this probability first in order to find a %
The z score is given by:
If we apply this formula to our probability we got this:
And we can find this probability with this difference:
And in order to find these probabilities using the normal standard distribution or excel and we got.
So we expect about 99.735% of values between $29 and $89