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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?

User Marlenny
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1 Answer

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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


\bar{x}\pm z(\sigma)/(√(n))\\\\=68\pm 1.645* (3.9)/(√(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).

User Andrea Antonangeli
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