Question

According to the World Health Organization (WHO) Child Growth Standards, the head circumference for boys at birth is normally distributed with a mean of 34.5cm and a standard deviation of 1.3cm. What is the z‑score for a boy born with a head circumference of 35.8cm?

Answer 1

Answer: the z score is 1

Explanation:

Since the head circumference for boys at birth is normally distributed,

we would apply the formula for normal distribution which is expressed as

z = (x - µ)/σ

Where

x = head circumference for boys at birth.

µ = mean head circumference

σ = standard deviation

From the information given,

µ = 34.5cm

σ = 1.3 cm

For a boy born with a head circumference of 35.8cm, the z score is

z = (35.8 - 34.5)/1.3

z = 1