Students in Physics and Chemistry a random sample was taken
from 20 students in Physics, from which an average of 3 hours per
week was obtained with a deviation. typical of 2.5 hours, and
another sample of 30 independent chemistry students from the
previous one, which presented an average of 2.8 hours, with a
deviation. typical 2.7h. Assuming that the weekly study hours of
the two types of students follow a normal distribution,
(a) Calculate a 95% confidence interval for...