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
#LearnwithBrainly
