Question: A large supermarket chain is interested in determining whether a difference exists between the mean shelf-life (in days) of Brand S bread and Brand H bread. The results are shown below.

Brand S Brand H
x1=4.1 days x2=5.2 days
s1=1.2 days s2=1.4 days
n1= 35 n2=35 days
Population Mean u1 Population Mean u2

Test the claim that there is a difference in the shelf-life of both brands. Decide whether the normal distribution or the t-distribution should be used for this two-sample test using the flowchart on page 443 in our textbook. Use all three levels of significance . Report the p-value of the test.