Question

In the waist circumference distribution (mean = 92.5 cm, standard deviation = 13.7 cm) for males aged 20–29, what percentage falls below 80 cm?

a) 15.87%
b) 23.85%
c) 84.13%
d) 76.15%

Answer 1

To find the percentage of males aged 20-29 with a waist circumference below 80 cm, calculate the z-score for this value and use the standard normal distribution table.

Step-by-step explanation:

To find the percentage of males aged 20-29 with a waist circumference below 80 cm, we need to calculate the z-score for this value and then use the standard normal distribution table.

The z-score for a given value x can be calculated using the formula z = (x - mean) / standard deviation.

So, for x = 80 cm, the z-score = (80 - 92.5) / 13.7 = -0.9147.

Looking up the z-score -0.9147 in the standard normal distribution table, we find that the area to the left of this z-score is 0.1792, which corresponds to approximately 17.92%.

Therefore, the percentage of males aged 20-29 with a waist circumference below 80 cm is approximately 17.92%.