Problem

Karen wants to advertise how many chocolate chips are in each Big Chip cookie at her bakery. She randomly selects a sample of 41 cookies and finds that the number of chocolate chips per cookie in the sample has a mean of 7.1 and a standard deviation of 2.2. What is the $95 \%$ confidence interval for the number of chocolate chips per cookie for Big Chip cookies? Enter your answers accurate to one decimal place (because the sample statistics are reported accurate to one decimal place).

Answer

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Answer

Final Answer: The $95 \%$ confidence interval for the number of chocolate chips per cookie for Big Chip cookies is \(\boxed{[6.4, 7.8]}\).

Steps

Step 1 :Given that the sample mean (\(\bar{x}\)) is 7.1, the sample standard deviation (s) is 2.2, and the sample size (n) is 41.

Step 2 :We are asked to find the 95% confidence interval for the number of chocolate chips per cookie. The z-score for a 95% confidence interval is approximately 1.96.

Step 3 :We can use the formula for a confidence interval, which is \(\bar{x} \pm z \frac{s}{\sqrt{n}}\).

Step 4 :Substituting the given values into the formula, we get \(7.1 \pm 1.96 \frac{2.2}{\sqrt{41}}\).

Step 5 :Calculating the above expression, we find that the 95% confidence interval is approximately [6.4, 7.8].

Step 6 :Final Answer: The $95 \%$ confidence interval for the number of chocolate chips per cookie for Big Chip cookies is \(\boxed{[6.4, 7.8]}\).

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