### Solution Found!

# Low-birth-weight babies Researchers in Norway analyzed

**Chapter , Problem R2.9**

(choose chapter or problem)

**QUESTION:**

**Low-birth-weight babies** Researchers in Norway analyzed data on the birth weights of 400,000 newborns over a 6-year period. The distribution of birth weights is Normal with a mean of 3668 grams and a standard deviation of 511 grams.\(^{17}\) Babies that weigh less than 2500 grams at birth are classified as low birth weight.''

(a) What percent of babies will be identified as low birth weight? Show your work.

(b) Find the quartiles of the birth weight distribution. Show your work

### Questions & Answers

**QUESTION:**

**Low-birth-weight babies** Researchers in Norway analyzed data on the birth weights of 400,000 newborns over a 6-year period. The distribution of birth weights is Normal with a mean of 3668 grams and a standard deviation of 511 grams.\(^{17}\) Babies that weigh less than 2500 grams at birth are classified as low birth weight.''

(a) What percent of babies will be identified as low birth weight? Show your work.

(b) Find the quartiles of the birth weight distribution. Show your work

**ANSWER:**

Step 1 of 3

a)

Babies that weigh less than 2500 grams at birth are classified as “low birth weight.” We are supposed to find the percentage of low birth weight babies. That is, we are supposed to find the percentage of babies whose weight is less than 2500 grams.

The z-value that corresponds to a baby weight less than 2500 grams at birth is:

\(z = \frac{{2500 - 3668}}{{511}}\)

\(z = - 2.29\)