Question

A sleep time of 15.9 hours per day for a newborn baby is at the 10h percentile of the distribution of sleep times for all newborn babies. Assuming the distribution is normal with a standard deviation of 0.5 hour, approximately what is the mean time, in hours per day, for newborn babies? A. 15.1 B. 15.3 С. 16.3 D. 16.5 E. 16.7

Answer 1

The mean time in hours per day for newborn babies is 16.5 hours ⇒ D

Step-by-step explanation:

A sleep time of 15.9 hours per day for a newborn baby is at the 10th

percentile of the distribution of sleep times for all newborn babies

Assuming the distribution is normal with a standard deviation of

0.5 hour

To find the mean time let us do that

1. Use the normal distribution table to find the corresponding z-score

   for 10th percentile

2. Use the rule μ = x - zσ, where μ is the mean, σ is the standard

    deviation and x is the score

3. Substitute the values of x, σ and z in the rule to find μ

Look to the normal distribution table to find z-score that equivalent

to the area = 10/100 = 0.1 (10th percentile)

∵ z-score = -1.28

∵ σ = 0.5 hour

∵ x = 15.9

∵ μ = x - zσ

- Substitute the values in the rule

∴ μ = 15.9 - (-1.28)(0.5)

∴ μ = 15.9 + 0.64

∴ μ = 16.54 ≅ 16.5 hours

The mean time in hours per day for newborn babies is 16.5 hours

Learn more:

You can learn more about the normal distribution curve in brainly.com/question/8799684

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