Assume that military aircraft use ejection seats designed for men weighing between 141.8 lb and 218 lb. If​ women's weights are normally distributed with a mean of 173.6 lb and a standard deviation of 49.8 ​lb, what percentage of women have weights that are within those​ limits? Are many women excluded with those​ specifications?

Respuesta :

Answer:

[tex]P(141.8<X<218)=P(\frac{141.8-\mu}{\sigma}<\frac{X-\mu}{\sigma}<\frac{218-\mu}{\sigma})=P(\frac{141.8-173.6}{49.8}<Z<\frac{218-173.6}{49.8})=P(-0.639<z<0.892)[/tex]

And we can find this probability with this difference and using the normal standard table:

[tex]P(-0.639<z<0.892)=P(z<0.892)-P(z<-0.639)=0.814-0.261= 0.553[/tex]

Then the answer would be approximately 55.3% of women between the specifications. And that represent more than the half of women

Step-by-step explanation:

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

[tex]X \sim N(173.6,49.8)[/tex]  

Where [tex]\mu=173.6[/tex] and [tex]\sigma=49.8[/tex]

We are interested on this probability

[tex]P(141.8<X<2188)[/tex]

And the best way to solve this problem is using the normal standard distribution and the z score given by:

[tex]z=\frac{x-\mu}{\sigma}[/tex]

If we apply this formula to our probability we got this:

[tex]P(141.8<X<218)=P(\frac{141.8-\mu}{\sigma}<\frac{X-\mu}{\sigma}<\frac{218-\mu}{\sigma})=P(\frac{141.8-173.6}{49.8}<Z<\frac{218-173.6}{49.8})=P(-0.639<z<0.892)[/tex]

And we can find this probability with this difference and using the normal standard table:

[tex]P(-0.639<z<0.892)=P(z<0.892)-P(z<-0.639)=0.814-0.261= 0.553[/tex]

Then the answer would be approximately 55.3% of women between the specifications. And that represent more than the half of women