# Question: Refer to the formula for a confidence interval in the

Refer to the formula for a confidence interval in the Focus on Formulas section.

a. Write the formula for a 90% confidence interval for a proportion.

b. Refer to Example 20.6. Construct a 90% confidence interval for the proportion of smokers who would quit after 8 weeks using a nicotine patch.

c. Compare the 90% confidence interval you found in part (b) to the 95% confidence interval used in the example. Explain which one you would present if your company were advertising the effectiveness of nicotine patches.

a. Write the formula for a 90% confidence interval for a proportion.

b. Refer to Example 20.6. Construct a 90% confidence interval for the proportion of smokers who would quit after 8 weeks using a nicotine patch.

c. Compare the 90% confidence interval you found in part (b) to the 95% confidence interval used in the example. Explain which one you would present if your company were advertising the effectiveness of nicotine patches.

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