A group of researchers wants to do a comparative study on auditory reaction time (ART) and visual reaction time (VRT) of Visual Arts majors. They took a sample of twenty college students who majored in Visual Arts, and each was given a unique serial number. In their study, two tasks were administered: (1) a VRT task where they need to press the spacebar of the computer keyboard once a red dot appears on the screen and (2) an ART task where a 20-second sound will be played, and the participants need to press the spacebar once the sound is presented. A randomization mechanism was done to determine which task would be administered first. The tables of the reaction times are shown below:

Two different blood pressure medicines are being compared to determine if the average reduction in blood pressure is the same for each medication. The goal of the study is to determine if the medications differ. Twenty men age 50-60 years old are selected for the study. Ten men are chosen at random to receive the first medication and the other 10 men receive the second medication. Each of the 20 men is monitored for one month to determine the change in blood pressure over that time. Minitab provides the 95% confidence interval for (mu1 - mu2) (2.63, 14.18) a. Interpret this 95% CI. b. What assumptions (be specific) are necessary to construct this CI?

A paper describes a study of the use of MRI (Magnetic Resonance Imaging) exams in the diagnosis of breast cancer. The purpose of the study was to determine if MRI exams do a better job than mammograms of determining if women who have recently been diagnosed with cancer in one breast have cancer in the other breast. The study participants were 940 women who had been diagnosed with cancer in one breast and for whom a mammogram did not detect cancer in the other breast.These women had an MRI exam of the other breast, and 111 of those exams indicated possible cancer. After undergoing biopsies, it was determined that 30 of the 111 did in fact have cancer in the other breast, whereas 81 did not. The women were all followed for one year, and four of the women for whom the MRI exam did not indicate cancer in the other breast were subsequently diagnosed with cancer that the MRI did not detect. The accompanying table summarizes this information.   CancerPresent Cancer NotPresent Total MRI…

Researchers investigate how the presence of cell phones influence the quality of human interaction.  Subjects are randomly selected from a population and divided into an experimental group that is asked to leave their phones in the front of the room and a control group that are not asked to leave their cell phones at the front of the room.  Subjects are left alone for 10 minutes and then asked to take a survey designed to measure quality of interactions they had with others in the experiment.  What statistical test is appropriate?

After visiting the Titanic, Captain Brain and Mr. Pinky are taking the Alvin submarine back to the surface of the water. They start 1900 meters below the surface of the water, and ascend at 62 meters per hour.Note: under the water is a negative number.Write an equation to model this situation (use mm for meters and hh for hours)

A team of researchers is interested in the effect on physical health of writing about thoughts and feelings associated with traumatic life events (expressive writing). The researchers recruit 30 undergraduate students to take part in the study and randomly assign them to be in an expressive writing group or a control group. Students in the expressive writing group are instructed to write four 20 - minute essays over four consecutive days about their most traumatic life experiences. Students in the control group write four 20 – minute essays over consecutive days describing their plans for that day. One week later, the researchers ask the students to rate their overall level of physical health (on a scale 0 = very poor health, to 100 = perfect health). EWG: 75, 86, 77, 91, 68, 74, 62, 93, 82, 79, 94, 56, 79, 86, 90, 97 CWG: 81, 76, 71, 70, 62, 50, 58, 63, 76, 64, 65, 72, 52, 59 The researchers were interested in identifying a positive or a negative health effect of expressive writing.…

A paper describes a study of the use of MRI (Magnetic Resonance Imaging) exams in the diagnosis of breast cancer. The purpose of the study was to determine if MRI exams do a better job than mammograms of determining if women who have recently been diagnosed with cancer in one breast have cancer in the other breast. The study participants were 950 women who had been diagnosed with cancer in one breast and for whom a mammogram did not detect cancer in the other breast. These women had an MRI exam of the other breast, and 101 of those exams indicated possible cancer. After undergoing biopsies, it was determined that 30 of the 101 did in fact have cancer in the other breast, whereas 71 did not. The women were all followed for one year, and four of the women for whom the MRI exam did not indicate cancer in the other breast were subsequently diagnosed with cancer that the MRI did not detect. The accompanying table summarizes this information. Cancer Cancer Not Present Present Total MRI…

Trichotillomania is a psychiatric illness that causes its victims to have an irresistible compulsion to pull their own hair. Two drugs were compared as treatments for trichotillomania in a study involving 13 women. Each women took clomipramine during one time period and desipramine during another time period in a double-blind experiment. Scores on a trichotillomania-impairment scale, in which high scores indicate greater impairment, were measured on each women during time period. The average of the 13 measurements for clomipramine was 6.2; the average of the 13 measurements for desipramine as 4.2. (a) A paired t test was used to test whether the mean difference between these two drugs is 0, resulting in a test statistics t∗ = 2.47. Find the sample standard deviation Sd. (b) Find a 95% confidence interval for the mean difference between the two drugs and give the conclusion.

An article included data from a survey of 2500 hiring managers and human resource professionals. The article noted that many employers are using social networks to screen job applicants and that this practice is becoming more common. Of the 2500 people who participated in the survey, 1250 indicated that they use social networking sites (such as Facebook, MySpace, and LinkedIn) to research job applicants. For the purposes of this exercise, assume that the sample is representative of hiring managers and human resource professionals -Why can this sampling distribution be considered normal? Explain and show why. -Construct a 95% confidence interval for the true population proportion of employers who use social networking sites to screen job applicants. Be sure to write a conclusion sentence that interprets your interval. (You may use Excel for this -Construct a 99% confidence interval for the true population proportion of employers who use social networking sites to screen job applicants.…

Dr. Mackintosh believes a new olfactory therapy would be more successful in promoting weight loss among obese patients. His patients are first weighed and then randomly assigned to olfactory therapy, dance therapy, or a control condition. At the end of the three weeks, the amount of weight lost is recorded. The results indicate no significant difference in the amount of weight lost between the three conditions. If true differences existed between the conditions, but they were not detected, what kind of error occurred?