Consider a study to evaluate the effect on college student grades of dormroom Internet connections. In a large dorm, half the rooms are randomlywired for high-speed Internet connections (the treatment group), and finalcourse grades are collected for all residents. Which of the following posethreats to internal validity, and why?a. Midway through the year, all the male athletes move into a fraternityand drop out of the study. (Their final grades are not observed.)b. Engineering students assigned to the control group put together alocal area network so that they can share a private wireless Internetconnection that they pay for jointly.c. The art majors in the treatment group never learn how to access theirInternet accounts.d. The economics majors in the treatment group provide access to theirInternet connection to those in the control group, for a fee.

The following is based on information from The Wolf in the Southwest: The Making of an Endangered Species, by David E. Brown (University of Arizona Press). Before 1918, the proportion of female wolves in the general population of all southwestern wolves was about 50%. However, after 1918, southwestern cattle ranchers began a widespread effort to destroy wolves. In a recent sample of 37 wolves, there were only 11 females. One theory is that male wolves tend to return sooner than females to their old territories, where their predecessors were exterminated. Do these data indicate that the population proportion of female wolves is now less than 50% in the region? Use α = 0.01. (a) What is the level of significance? State the null and alternate hypotheses. O Ho: P 0.5 O Ho: P = 0.5; H₁: p 5 and nq > 5. O The Student's t, since np > 5 and ng > 5. The standard normal, since np < 5 and nq < 5. O The Student's t, since np < 5 and nq < 5. What is the value of the sample test statistic? (Round…

A warehouse manager wants to know if there is an association between the shift worked and being on time for work. To investigate, he selects a random sample of 70 workers and classifies each one according to the shift they worked most recently and whether they were on time for work. He was unable to classify a substantial number of people as being on time, so he classified those individuals as unknown. The data are displayed in the table.   The manager would like to know if these data provide convincing evidence of an association between the shift worked and being on time in the large population of all workers at this warehouse. The random and 10% conditions are met. Is the Large Counts condition met? Yes, the smallest expected count is 5, so all expected counts are at least 5. Yes, the smallest expected count is 8.54, so all expected counts are at least 5. No, the smallest expected count is 2.56, so the expected counts are not all at least 5. No, the smallest expected count is…

24)  Some research has shown that swearing can help reduce ratings of pain (Stephens, Atkins, & Kingston, 2009). In one such study, each participant was asked to plunge a hand into icy water and keep it there as long as the pain would allow. In one condition, the participants repeated their favorite curse words while their hands were in the water. In the other condition, the participants repeated a neutral word. In addition to lowering the participants’ perception of pain, swearing also increased the amount of time they were able to tolerate the pain. Data similar to the results obtained in their study are shown in the following table.      Amount of Time (in Seconds)   Participant Swear Words Neutral Words 1 94 59 2 70 61 3 52 47 4 83 60 5 46 35 6 117 92 7 69 53 8 39 30 9 51 56 10 73 61   Do these data indicate a significant difference in pain tolerance between the two conditions?…