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