Dr. smith determined that that the average human pregnancy is 266 days from conception to birth. Assume the length of human pregnancies can be approximated by a normal distribution with a mean of 266 days and standard deviation = 16 days. Find the prob. that a pregnancy will last:__________

Respuesta :

Answer:

[tex]P(x< 240) = 0.0521[/tex]

Step-by-step explanation:

Given

[tex]\bar x = 266[/tex]

[tex]\sigma = 16[/tex]

Required

[tex]P(x < 240)[/tex] --- pregnancy will last less than 240 days

First, calculate the z score

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

Where:

[tex]x = 240[/tex]

So, we have:

[tex]z = \frac{240 - 266}{16}[/tex]

[tex]z = \frac{-26}{16}[/tex]

[tex]z = -1.625[/tex]

So:

[tex]P(x< 240) = P(z < -1.625)[/tex]

From z probability:

[tex]P(z < -1.625) = 0.052081[/tex]

[tex]P(z < -1.625) = 0.0521[/tex] --- approximated

So:

[tex]P(x< 240) = 0.0521[/tex]