the mean lung capacity for nonsmoking males in the population aged 50 is 2.2 liters. an investigator wants to examine if the mean lung capacity are significantly diffrent among former smokers of similar background(i.e, males aged 50 who smoked in the past and are not currently smoker). a random sample of 28 former smokers is selected. their lung capacity have a mean of 2.0 liters with a standard devision of 0.41 liters.

calculate the appropirate test at the 1% level of significance. decide on a 1- tail or 2- tail test based on the goals of the research.

the value of the calculated test statistic=

the critical value=

regarding the null hypothesis