Question

The sales of medicines in a certain pharmacy behaves with a variable with a normal distribution with means of 2000 pesos and variance of 62500
a) What is the probability that the pharmacy will sell more than 1500 pesos?
b) How many standard deviations is a sales value of 3300 pesos in the scope of the media? Can it be considered atypical (unusual) or not? Why?
c) What is the 99th percentile of sales?
d) What is the probability that the sales are exactly 2,500 pesos?

Answer 1

Let X denotes the sales of medicines in a certain pharmacy

X ~ Normal(2000, 62500) or X ~ Normal(2000, 250²)

a) The probability that the pharmacy will sell more than 1500 pesos

b) z-score

Since z-score value is quite big enough, so we can say that this value is atypical.

c) To find the 99th percentile of sales,

i.e. to find x such that

d) The probability that the sales are exactly 2,500 pesos