As part of a health study, the heart rates of random samples of newborns from two ethnic groups were recorded. A summary of the data is given below.
Sample Size Group A 100 Group B 80
Sample Mean Group A124.8 Group B 130.2
Sample Standard deviation Group A11.1 Group B 12.4
(a) Test at a = 0.01 if the mean heart rate for newborns from ethnic group B is significantly higher than for those from group A. Find the P-value.
(b) Estimate the mean difference in heart rate for newborns between the two ethnic groups using a 95% confidence interval.