Question

Lengths of pregnancies​ (in humans) have a mean of 268.3 days and a standard deviation of 15.1 days. A woman tracked her pregnancy and found it to be 310 days. Find the z score for 310 days. Is such a length​ unusual? The z score is 2.8-2.76 2.76. ​(Round to two decimal places as​ needed.) Is a pregnancy length of 310 days​ unusual? A. ​Yes, because its corresponding z score is less than 2. B. ​Yes, because its corresponding z score is greater than 2. C. ​No, because its corresponding z score is greater than 2. D. ​No, because its corresponding z score is less than 2.

Answer 1

Option B) ​Yes, because its corresponding z score is greater than 2.

Explanation:

We are given the following information in the question:

Mean, μ = 268.3 days

Standard Deviation, σ = 15.1 days

We are given that the distribution of lengths of pregnancies is a bell shaped distribution that is a normal distribution.

Formula:

`z_(score) = \displaystyle(x-\mu)/(\sigma)`

For x = 310

`z = \displaystyle(310 - 268.3)/(15.1) = 2.77`

Since the obtained z score is greater than 2 we could that 310 is unusual.

Option B) ​Yes, because its corresponding z score is greater than 2.