Babies born weighing 2500 grams (about 5.5 pounds) or less are called low-birth-

Question

Babies born weighing 2500 grams (about 5.5 pounds) or less are called low-birth-weight babies, and this condition sometimes indicates health problems for the infant. The mean birth weight for children born in a certain country is about 3408 grams (about 7.5pounds). The mean birth weight for babies born one month early is 2696 grams. Suppose both standard deviations are470 grams. Also assume that the distribution of birth weights is roughly unimodal and symmetric. Complete parts a through c below.

a. Find the standardized score (z-score), relative to all births in the country, for a baby with a birth weight of 2500 grams. z= nothing (Round to two decimal places as needed.)

b. Find the standardized score for a birth weight of 2500 grams for a child born one month early, using 26962696 as the mean. z= nothing

(Round to two decimal places as needed.)

.

c. For which group is a birth weight of 2500 grams more common? Explain what that implies. Unusual z-scores are far from 0. Choose the correct answer below.

A. A birth weight of 2500 grams is more common for all births in the country. This makes sense because the group of all births in the country is much larger than the group of births that are one month early. Therefore, more babies will have low birth weights among all births in the country

B. A birth weight of 2500 grams is more common for babies born one month early. This makes sense because babies gain weight during gestation, and babies born one month early had less time to gain weight.

C. A birth weight of 2500 is equally as common to both groups.

D.It cannot be determined to which group a birth weight of 2500 grams is more common.

Explanation / Answer

a) Mean = 3408, Standard deviation = 470

So,

z - score for birth weight of 2500 grams will be:

(2500 - 3408)/ 470

= -1.93

b) z - score for birth weight of 2500 grams considering 1 month early birth is:

(2500 - 2696)/ 470

= - 0.42

c) Option B is correct.

Related Questions

Navigate

• Browse (All)
• Browse B
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.