A study of 40 English composition professors showed that they spent, on average, 13 minutes correcting a student's term paper. The standard deviation was 2 min. a. Find and the 90% confidence interval for the mean grading time of all composition papers. < μ < b. intrepret the meaning of the confidence interval you found in part a. b. Does the confidence interval, at 90% confidence level, provide sufficient evidence that the mean time English composition professors spend on grading term papers exceeds 11 minutes? Write an appropriate inequality to justify your answer.

The probability that a u.s. resident has traveled to canada is 0.18 and to mexico is 0.09. a. if traveling to canada and traveling to mexico are independent events, what is the probability that a randomly-selected person has traveled to both? (page 109 in the book may ) b. it turns out that only 4% of u.s. residents have traveled to both countries. comparing this with your answer to part a, are the events independent? explain why or why not. (page 119 may ) c. using the %’s given, make a venn diagram to display this information. (don’t use your answer to part a.) d. using the conditional probability formula (page 114 in the book) and the %’s given, find the probability that a randomly-selected person has traveled to canada, if we know they have traveled to mexico.