Question

A study was being conducted about birth weights of babies at a local hospital and found the average to be 7.6 pounds with a standard deviation of 1.3 pounds (the distribution was approximately normal). Many pre-mature births weights are in the lowest 1% of births. What would be the birth weight associated with the lowest 1%?

Answer 1

Answer:

The birth weight associated with the lowest 1% is 4.6 pounds.

Step-by-step explanation:

Let X represent the birth weights of babies.

It is provided that $X\sim N(7.6,1.3^{2})$

It is also provided that many pre-mature births weights are in the lowest 1% of births.

Let x represent the births weights that are in the lowest 1% of births.

That is, P (X < x) = 0.01.

⇒ P (Z < z) = 0.01

The corresponding z-score is, z = -2.33.

Compute the value of x as follows:

$z=\frac{s-\mu}{\sigma}\\\\-2.33=\frac{x-7.6}{1.3}\\\\x=7.6-(1.3\times 2.33)\\\\x=4.571\\\\x\approx 4.6$

Thus, the birth weight associated with the lowest 1% is 4.6 pounds.