Question

The respiratory rate (in breaths per minute) in newborns varies according to a distribution that is approximately Normal, with a mean of 50 and a standard deviation of 5. Use Excel to answer this question: What is the probability that a randomly chosen newborn has a respiratory rate between 40 and 55 breaths per minute

Answer 1

`P(40<X<55)`

And since we need to use excel the code in order to find the answer would be:

=NORM.DIST(55,50,5,TRUE)-NORM.DIST(40,50,5,TRUE)

And the answer would be:

`P(40<X<55)=0.819`

Explanation:

Let X the random variable that represent the respiratory rate of a population, and for this case we know the distribution for X is given by:

`X \sim N(50,5)`

Where
`\mu=50` and
`\sigma=5`

We are interested on this probability

`P(40<X<55)`

And since we need to use excel the code in order to find the answer would be:

=NORM.DIST(55,50,5,TRUE)-NORM.DIST(40,50,5,TRUE)

And the answer would be:

`P(40<X<55)=0.819`