Answer:
[tex]P(X<31)=P(\frac{X-\mu}{\sigma}<\frac{31-\mu}{\sigma})=P(Z<\frac{31-24.8}{6.2})=P(z<1)[/tex]
And we can find this probability using the normal standard distribution or excel and we got:
[tex]P(z<1)= 0.84[/tex]
And if we convert this into % we got 84% so then the best solution would be:
84%
Step-by-step explanation:
Let X the random variable that represent the size of gasoline tanks of a population, and for this case we know the distribution for X is given by:
[tex]X \sim N(24.8,6.2)[/tex]
Where [tex]\mu=24.8[/tex] and [tex]\sigma=6.2[/tex]
We are interested on this probability
[tex]P(X<31)[/tex]
And we can use the z score formula given by:
[tex]z=\frac{x-\mu}{\sigma}[/tex]
Using the last formula we got:
[tex]P(X<31)=P(\frac{X-\mu}{\sigma}<\frac{31-\mu}{\sigma})=P(Z<\frac{31-24.8}{6.2})=P(z<1)[/tex]
And we can find this probability using the normal standard distribution or excel and we got:
[tex]P(z<1)= 0.84[/tex]
And if we convert this into % we got 84% so then the best solution would be:
84%
