A doctor wants to determine if a new medication for cholesterol is more effective than the previous medication. The doctor asks her patients if they would like to take part in a study for a new medication, and 30 patients currently taking medication for cholesterol volunteer to participate. Which of the following would be an appropriate procedure for this experiment? The doctor needs to randomly assign 15 patients to the new medication and 15 to the original medication to even out the variability between the patients. The doctor needs to assign the first 15 patients to the new medication and 15 to the original medication to even out the variability between patients. The doctor needs to let the 30 patients choose which medication they are going to take through use of a survey to determine whether they want to participate in the experiment. The doctor needs to randomly assign the 30 patients to the new medication to even out the variability between the patients and to determine if their cholesterol level is lowered.

A researcher believes that there may be a negative association between the quantity of fertilizer used and the percentage of the population who live in rural areas in different countries. The data below shows the percentage of the population who live in rural areas and the fertilizer use measured in kg per hectare, for a random sample of 11 countries. 33%= 76kg, 6%=44kg, 58%= 6kg, 35%=68kg, 81%=3kg, 69%=10kg, 61%=7kg, 7%=176kg,74%=5kg, 71%=137kg, 17%=157kg Use the Spearman's rank order coefficient method to affirm or disagree with the researchers assumption.

Suppose you were presented with the results of a study comparing two different training methods for basketball athletes. You are told 32 athletes were randomly assigned to the two groups so that 16 were in the group A and 16 were in the group B. At the end of the session, the average scores (wins versus losses) of the two groups/teams were compared and a difference of 10% was observed ( the first team had 10% more wins than the second). The coach observer reports two- sample t-test shows this difference is statistically significant. How would you interpret these findings? What questions or concerns would you have? How might this type of study be improved? Hint: Consider the possibility that the test performed was not the appropriate one.

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. Identify the independent variable along with each level and the dependent variable.

The authors of a paper randomly selected two samples of patients admitted to the hospital after suffering a stroke. One sample was selected from patients who received biofeedback weight training for 8 weeks, and the other sample was selected from patients who did not receive this training. At the end of 8 weeks, the time it took (in seconds) to stand from a sitting position and then to sit down again (called sit-stand-sit time) was measured for the people in each sample. Data consistent with summary quantities given in the paper are given below. For purposes of this exercise, you can assume that the samples are representative of the population of stroke patients who receive the biofeedback training and the population of stroke patients who do not receive this training. Biofeedback Group 2.1 2.8 4.5 2.3 2.9 4.3 3.4 4.2 3.4 3.7 3.0 3.7 3.7 2.5 3.3 No Biofeedback Group 5.2 4.8 4.0 4.3 4.8 4.4 4.3 5.2 3.5 4.3 5.2 4.5 4.1 3.5 4.0   Conduct a test of hypothesis to test whether…

Peter Boag, studied the inheritance of beak depth in Galapagos finches by looking at the relationship between parent beak depth (in mm) and that of their offspring.  He collected two sets of parent offspring data, once in 1976 and again in 1978.  For both years he followed birds to determine which pairs belonged to which nests. Most of the parents had been previously captured so their beak depths were known.  He then captured the offspring when they fledged and measured their beak depth.  He calculated the "midparent" beak depth (the average beak depth of the two parents) and then compared that to beak depth of their offspring.   Use regression analysis to estimate heritability for the trait beak depth from the Galapagos finches data in the above table.

Scientists are interested in the placebo effect on adults with arthritis. They randomly choose 15 adults with arthritis and give them 2 treatments: effective drug and placebo for 1 week at different times. At the end of each week, the scientists ask the participants to rate their arthritic pain level on a scale of 1-5, where 1 is little pain and 5 is a lot of pain. The researchers then take the difference of their pain levels (affective drug - placebo). The data are below. 0, 1, 2, 2, 0, -1, 3, 1, 2, -1, 0, 1, -2, -1, -6 (a) Find the 5-number summary for the difference of arthritic pain levels. Minimum = Q₁ = Median = USE SALT Q3 = Maximum = (b) One of the conditions for inference for population mean difference of paired data is normality. Outliers within a data set cast a shadow of doubt upon the normality of the population distribution. Use the 5-number summary calculated in part (a) to determine if there are any outliers in the data set. Which of the values, if any, is an outlier…

A psychologist would like to examine the effects of a new drug on the activity level of animals. Three samples of rats are selected with n=5 in each sample. One group gets no drug, one group gets s small dose, and the third group gets a large dose. The psychologist records the activity level for each animal. The data from this experiment are presented below.   No drug Small dose Large dose 5, 3 , 1 , 1 , 5 5, 5, 9, 6, 5 10, 12, 9, 6, 8 =3, SS=16 =6, SS=12 =9, SS=20   Do these data indicate any significant differences among the three groups? Test with α=0.05.                        Compute the effect size and interpret the result.

A group of statisticians decides they will answer the question:  Has the wolf reintroduction to Yellowstone been detrimental to elk herds in the park?  They decide that each of the four data scientists will take a quadrant of the park to collect a sample from as randomly as possible.  They decide they will collect the sample during the winter, the time the elk herds are most stressed.  They agree to trust each others professional judgement when it comes to the health of the individual elk in the herd.  They will give each elk a grade out of 3pts: 1 pt for sick, 2pts for fair, and 3pts for healthy.  They then share their data and compare to create a final report on the overall health of the elk in the park. In this scenario, what kind of random sampling did the statisticians use?

The authors of a paper randomly selected two samples of patients admitted to the hospital after suffering a stroke. One sample was selected from patients who received biofeedback weight training for 8 weeks, and the other sample was selected from patients who did not receive this training. At the end of 8 weeks, the time it took (in seconds) to stand from a sitting position and then to sit down again (called sit-stand-sit time) was measured for the people in each sample. Data consistent with summary quantities given in the paper are given below. For purposes of this exercise, you can assume that the samples are representative of the population of stroke patients who receive the biofeedback training and the population of stroke patients who do not receive this training. Biofeedback Group 2.2 2.9 4.6 2.4 3.0 4.4 3.5 4.3 3.5 3.8 3.1 3.8 3.8 2.6 3.4 No Biofeedback Group 5.2 4.8 4.0 4.3 4.8 4.4 4.3 5.2 3.5 4.3 5.2 4.5 4.1 3.5 4.0   Conduct a test of hypothesis to test whether…