Complete question :
The birthweight of newborn babies is Normally distributed with a mean of 3.96 kg and a standard deviation of 0.53 kg. Find the probability that an SRS of 36 babies will have an average birthweight of over 3.9 kg. Write your answer as a decimal. Round your answer to two places after the decimal
Answer:
0.75151
Step-by-step explanation:
Given that :
Mean weight (m) = 3.96kg
Standard deviation (σ) = 0.53kg
Sample size (n) = 36
Probability of average weight over 3.9
P(x > 3.9)
Using the z relation :
Zscore = (x - m) / (σ / √n)
Zscore = (3.9 - 3.96) / (0.53 / √36)
Zscore = - 0.06 / 0.0883333
Zscore = −0.679245
Using the Z probability calculator :
P(Z > - 0.679245) = 0.75151
= 0.75151
