The following table shows the summary statistic of the cholesterol levels of two groups of men in 2014.
From 25 to 40 years old, the mean is 224, standard deviation is 5.5 and the sample size is 12.
From 41 to 55 years old, the mean is 230, standard deviation is 7 and the sample size is 10.
It is assumed that the population standard deviations of cholesterol levels in both groups are the same.
a) In 2013, the mean cholesterol level of men from 25 to 40 years old is 218. Test the claim that
the mean cholesterol level of men from 25 to 40 years old has increased in 2014. Use the
P-value method. State the assumptions required.
b) A researcher claims that there is a difference in the cholesterol levels of men from 25 to 40 years
old and from 41 to 55 years old. From the data collected in 2014 above, is there enough evidence to support the claim? Conduct a two-sample test at the 5% significance level to explain your answer.
5 answers