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?
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 / ...
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.