An experiment was conducted to estimate the effect of smoking on the blood pressure of a group of 39 cigarette smokers. The difference for each participant was obtained by taking the difference in the blood pressure readings at the beginning of the experiment and again five years later. The sample mean increase, measured in millimetres of mercury, was x = 9.8. The sample standard deviation was s = 5.2. Estimate the mean increase in blood pressure that one would expect for cigarette smokers over the time span indicated by the experiment. Find the 95% margin of error. (Round your answer to two decimal places.) Describe the population associated with the mean that you have estimated. The population is made up of the differences in blood pressure for all smokers under 40 and smokers over 40. The population is made up of the differences in blood pressure for all smokers and nonsmokers between the beginning of the experiment and five years later. The population is made up of the differences in blood pressure for all smokers between the beginning of the experiment and five years later. The population is made up of the differences in blood pressure for all smokers and nonsmokers. The population is made up of the differences in blood pressure for all smokers and smokers over 40. Need Help?