1. Give a 90% confidence interval, forμ1−μ2μ1-μ2 given the following information.
n1=45, ¯x1=2.97, s1=0.88
n2=20, ¯x2=3.44, s2=0.83
........ ± ........ Rounded to 2 decimal places.
2. A travel magazine conducts an annual surveywhere readers rate their favorite cruise ship. Ships are rated on a10 point scale, with higher values indicating better service. Asample of 30 ships that carry fewer than 500 passengers resulted inan average rating of 8.97 with standard deviation of 0.98. A sampleof 35 ships that carry more than 500 passengers resulted in anaverage rating of 9.13 with a standard deviation of 0.6.
Give a 95% confidence interval of the difference between thepopulation mean ratings for smaller ships and the population meanratings for larger ships. (Note, the order of subtractionmatters...look at the wording carefully.)
...................... ±................... Rounded to 2 decimalplaces.
