1. Marine scientists have found large concentrations of DNA on the ocean floor. One hypothesis is that the DNA is coming from phytopigments within diatoms that die in the water column and sink to the ocean floor. Please see the columns "dna" and "phyto" in your HW5a spreadsheet. Does phytopigment concentration help explain DNA concentration? a. Report the null and alternate hypothesis b. Examine the assumptions of normality for the response variable as well as evenness of residuals (show and interpret a residual plot) c. Show a scatterplot of the data with the best-fitting line d. Report run the regression and report test statistic, df, and P value e. Do you accept or reject the null? Interpret your results in one or two sentences. 2. A study investigated the possible link between body mass index (BMI) and plasma testosterone concentrations in a sample of 50 adolescent males between the ages of 14 and 20. Please see columns labeled BMI and testosterone in your HW5a spreadsheet. a. Report the null and alternate hypothesis b. Examine the assumptions of normality for the response variable as well as evenness of residuals (show and interpret a residual plot) c. Show a scatterplot of the data with the best-fitting line d. Report run the regression and report test statistic, df, and P value e. Do you accept or reject the null? Interpret your results in one or two sentences. * s 1. Marine scientists have found large concentrations of DNA on the ocean floor. One hypothesis is that the DNA is coming from phytopigments within diatoms that die in the water column and sink to the ocean floor. Please see the columns "dna" and "phyto" in your HW5a spreadsheet. Does phytopigment concentration help explain DNA concentration? a. Report the null and alternate hypothesis b. Examine the assumptions of normality for the response variable as well as evenness of residuals (show and interpret a residual plot) c. Show a scatterplot of the data with the best-fitting line d. Report run the regression and report test statistic, df, and P value e. Do you accept or reject the null? Interpret your results in one or two sentences. 2. A study investigated the possible link between body mass index (BMI) and plasma testosterone concentrations in a sample of 50 adolescent males between the ages of 14 and 20. Please see columns labeled BMI and testosterone in your HW5a spreadsheet. a. Report the null and alternate hypothesis b. Examine the assumptions of normality for the response variable as well as evenness of residuals (show and interpret a residual plot) c. Show a scatterplot of the data with the best-fitting line d. Report run the regression and report test statistic, df, and P value e. Do you accept or reject the null? Interpret your results in one or two sentences. * s
