# Nicotine confidence interval estimates

Refer to Data Set 4 in Appendix B and assume that the samples are simple random samples obtained from normally distributed populations.

a. Construct a 95% confidence interval estimate of the mean amount of nicotine in cigarettes that are king size, nonfiltered, nonmenthol, and non-light.

b. Construct a 95% confidence interval estimate of the mean amount of nicotine in cigarettes that are 100 mm, nonfiltered, nonmenthol, and non-light.

c. Compare the results. Do filters on cigarettes appear to be effective?

https://brainmass.com/statistics/statistical-theory/nicotine-confidence-interval-estimates-646128

#### Solution Preview

a

Refer to the Excel spreadsheet for the computations. Computations have been rounded to 3 decimal places.

Sample size = 25 (there are 25 values in the list)

Mean = 1.256

Sample standard deviation = 0.233

t-value = 2.064

Margin of Error = 0.096

Compute the Margin of error by hand using the values above as follows:

2.064 * 0.233 / ...

#### Solution Summary

Using the Nicotine in cigarettes example, the Excel file contains all formulas and computations: the 95% confidence interval estimates and compares the results. A step-by-step solution is provided.