Chapter 9, Problem 9.78CRP

Some commercial airlines recirculate about half the air in the cabin during flights as a way to improve fuel efficiency. Other airlines make a policy of NOT recirculating the air and instead, have fresh air from the atmosphere constantly being inserted into the cabin with the “old” air being pumped out of the plane. A total of 1100 passengers flying from San Francisco to Denver were used for an experiment. After their flight, they were each given a list of symptoms associated with the common cold. They were asked to report if they experienced cold symptoms within 24 hours of the flight landing. Of the 517 passengers who flew on planes that recirculate the air, 108 reported post-flight cold symptoms. Of the 583 passengers who flew on airlines that do not use recirculation in the cabin, 110 reported symptoms. Suppose now that we want to use the recirculation of air data to explore “Goal #2”, which is to resolve a hypothesis test about . a) If we want to resolve this hypothesis…

A study is run to evaluate the effectiveness of an exercise program in reducing systolic Ate blood pressure in patients with pre-hypertension. A total of 15 patients with pre- 12 hypertension enrolled in the study, and their systolic blood pressures are measured. Each patient then participated in an exercise training program where they learned proper techniques and execution of a series of exercises. Patients were instructed to do the exercise program three times per week for six weeks. After six weeks, systolic blood pressures were again measured, and data were recorded. This study sought to determine if there is a difference in systolic blood pressures after participating in the exercise program as compared to before. What is the most appropriate statistical test to be used to answer the research objectives? a. Spearman Correlation Coefficient b. Pearson Correlation Coefficient c. Wilcoxon Signed Ranks Test d. Mann-Whitney U Test

College students at a local community college take an average of 3.3 years to complete an AA (only counting semesters when officially enrolled).  A chancellor at a community college believes that the time to graduation could be high because of the large number of students who move out of their parents homes and move in with other students their age.  He theorizes that students who move into their own apartments will party more, focus less on their studies, and have to spend more time earning money, which will make them take longer to graduate.  To test his theory, the chancellor randomly selects 36 freshman who are planning to earn an AA and choosing to live in their own apartments while attending the college. The students in the sample took an average of 3.8 years to earn their AA (SS = 50.4).  Is there sufficient evidence to indicate, at the 5% level of significance (two-tailed), that community college students who lived on their own took more time to earn an AA?   Estimate Cohen's…

Please show your work for part a- d

The "cold start ignition time" of an automobile engine is being investigated by a gasoline manufacturer. Two gasoline formulations were made and the following times, in seconds, were obtained for the same test vehicle. Formulation 1: 1.75 1.92 2.62 2.35 3.09 3.15 2.53 3.40 1.91 Formulation 2: 1.83 1.99 3.13 3.29 2.65 2.87 2.46 1.89 3.35 a. Calculate the mean for each formulation. b. Which of the two formulations has a more varied set of data? What is your statistical basis for this?

Blood clotting is due to a sequence of chemical reactions. The protein thrombin initiates blood clotting by working with another protein, prothrombin. It is common to measure an individual's blood clotting time as prothrombin time, the time between the start of the thrombin-prothrombin reaction and the formation of the clot. Researchers wanted to study the effect of aspirin on prothrombin time. a)Fill in the values for the differences, absolute value of the differences, and signed ranks.  b)Calculate T− and T+

An advertising agency is testing the effectiveness of a new commercial. They are trying out the commercial in three different time lengths ​(15​, 30​, and 60 ​seconds) and two formats ​(animated vs. live action​). Each test audience will rate the product after seeing the commercial shown in one way. What is a description of this​ study?

In his doctoral thesis, L. A. Beckel (University of Minnesota, 1982) studied the social behavior of river otters during the mating season. An important role in the bonding process of river otters is very short periods of social grooming. After extensive observations, Dr. Beckel found that one group of river otters under study had a frequency of initiating grooming of approximately 1.7 for each 10 minutes. Suppose that you are observing river otters for 40 minutes. Let r = 0, 1, 2, ... be a random variable that represents the number of times (in a 40-minute interval) one otter initiates social grooming of another. Lambda = 6.8 (b) Find the probabilities that in your 40 minutes of observation, one otter will initiate social grooming four times, five times, and six times. (Round your answers to four decimal places.) P(4) =   P(5) =   P(6) =

A clinician interested in agoraphobia (fear of public places) tests a new treatment method. She samples five agoraphobics from her clinic and has them report how many times they ventured out of their houses (on their own) in the past month. They then received relaxation training and were introduced to trips away from their homes at gradually increasing durations. After 2 months, subjects again reported how many times they ventured (on their own) out of their houses. The data are below. Assess whether there is a significant change in trips outside the home from before to after therapy. a. Report and interpret an effect size b. what type of error might you be making?