A biostatistician finds the relationship between the number of weeks (X) spent in a hospital and number of seizures per week (Y) andis described by the following equation: .  This is based on a sample size of 50 patients and the associated coefficient of correlation is r = .93. Using this information above, answer the following question: How do you interpret r = .93?

Calculate the lower bound of a 95% confidence interval for the difference in sample means for the given data (round your answer to 4 decimal places):   DO NOT ASSUME THE POPULATION STANDARD DEVIATIONS OF THE TWO SAMPLES ARE EQUAL Group 1: Carpenter Sample mean = 60000 Sample standard deviation = 5500 Sample size = 10   Group 2: Crane Operator Sample mean = 62500 Sample standard deviation = 2500 Sample size = 14

Five hundred women are enrolled in a study to evaluate the accuracy of a test for pregnancy. 200 of the women were actually pregnant. 170 of the pregnant women had a positive test as did 40 of the women who were not pregnant. What is the probability (i.e., NPV) that a woman is not pregnant given that she tested negative on a screening test? Test                         Pregnant? Yes No Total + 170 40 210 – 30 260 290 Total 200 300 500

Conduct a hypothesis test based on the following information using a significance level of 1%: Research Question: Are people running more than 20.95 miles per week? Population standard deviation was NOT KNOWN Test statistic = 2.57 Sample size = 25

Using the information below calculate the predicted value for Y for the given value of X. Y (Dependent Variable) = Cost of a car in thousands of dollars (i.e. Y = 1 means one-thousand dollars) X (Independent Variable) = Miles per Gallon in city traffic   yhat = 28.1 + 0.62*X   On average how many thousands of dollars would a car cost if it gets 15 Miles per Gallon in city traffic (round your answer to 4 decimal places)?

Conduct a hypothesis test based on the following information using a significance level of 1%: Research Question: does the proportion of students taking out student loan debt equal 50%?   Test statistic = 2.83 sample size = 50

Select the appropriate interpretation for the slope of the linear regression equation below. Y (Dependent Variable) = Cost of an annual pass to Disney in dollars X (Independent Variable) = Average number of people who visit each day in thousands of people   yhat = 2122.86 – 30*X

Conduct a hypothesis test based on the following information using a significance level of 10%: Research Question: Do carpenters earn different salaries than accountants? Assume population variances for the two groups are equal to each other Group 1 = Carpenters Group 2 = Accountants Test statistic = 2.65 Group 1 Sample size = 15 Group 2 Sample size = 19

Conduct a hypothesis test based on the following information using a significance level of 5%: Research Question: Is the proportion of democrats who trust science different from the proportion of republics who trust science?   Group 1 = Democrats Group 2 = Republicans Test statistic = 0.88 Group 1 Sample size = 36 Group 2 Sample size = 44

Suppose you wish to compare the mean GPA of students in the College of Public Health to the mean GPA of students in the college of Medicine at USF.  If you have a list of all the students that fit into your population of interest and break them up into 50 sampling intervals to take every 3 person from each sampling interval, what type of sampling are you doing?