In: Statistics and Probability
1. Give a 90% confidence interval, for μ1−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 survey
where readers rate their favorite cruise ship. Ships are rated on a
10 point scale, with higher values indicating better service. A
sample of 30 ships that carry fewer than 500 passengers resulted in
an average rating of 8.97 with standard deviation of 0.98. A sample
of 35 ships that carry more than 500 passengers resulted in an
average rating of 9.13 with a standard deviation of 0.6.
Give a 95% confidence interval of the difference between the
population mean ratings for smaller ships and the population mean
ratings for larger ships. (Note, the order of subtraction
matters...look at the wording carefully.)
...................... ±................... Rounded to 2 decimal places.