Answer:
a) 81.5%
b) 95%
c) 75%
Step-by-step explanation:
We are given the following information in the question:
Mean, μ = 266 days
Standard Deviation, σ = 15 days
We are given that the distribution of length of human pregnancies is a bell shaped distribution that is a normal distribution.
Formula:
a) P(between 236 and 281 days)
b) a) P(last between 236 and 296)
c) If the data is not normally distributed.
Then, according to Chebyshev's theorem, at least data lies within k standard deviation of mean.
For k = 2
Atleast 75% of data lies within two standard deviation for a non normal data.
Thus, atleast 75% of pregnancies last between 236 and 296 days approximately.