Question

The gestation time of cats is approximately 68 days with a standard deviation of 3.9 days and is approximately Normally distributed. A sample of 35 kittens was selected. Assume that these are kittens that can be considered a random sample. What is a 90% confidence interval for the mean gestation time of kittens?

Answer 1

Answer:  90% confidence interval would be (66.92,69.08).

Step-by-step explanation:

Since we have given that

Number of kittens = n = 35

Mean = 68 days

Standard deviation = 3.9 days

We need to find the 90% confidence interval.

So, z= 1.645

So, intervals would be

$\bar{x}\pm z\dfrac{\sigma}{\sqrt{n}}\\\\=68\pm 1.645\times \dfrac{3.9}{\sqrt{35}}\\\\=68\pm 1.08\\\\=(68-1.08,68+1.08)\\\\=(66.92,69.08)$

Hence, 90% confidence interval would be (66.92,69.08).