Question

From “The Practice of Statistics in the Life Sciences” by Baldi and Moore. Obesity in adult males is associated with lower levels of sex hormone. A study investigated a possible link between obesity and plasma testosterone concentrations in adolescent males between the ages of 14 and 20 years. Here are the data for 25 obese adolescent males, measured in nanomoles per liter of blood (nmol/l): 0.30 0.24 0.19 0.17 0.18 0.23 0.24 0.06 0.15 0.17 0.18 0.17 0.15 0.12 0.25 0.25 0.25 0.32 0.35 0.37 0.39 0.46 0.49 0.42 0.36

(a) Test whether the average plasma testosterone concentrations in adolescent males between 14 and 20 years of age is 0.25 nmol/l or not. [4 marks]

(b) Suppose we have an interest in knowing whether the average plasma testosterone concentrations in adolescent males between 14 and 20 years of age is greater than 0.25 nmol/l. Test this situation. [4 mark]

(c) Suppose we have an interest in knowing whether the average plasma testosterone concentrations in adolescent males between 14 and 20 years of age is less than 0.25 nmol/l. Test this situation. [4 marks]

Answer 1

Step 1 : Find the mean and std. Deviation of the data

(a) Test whether the average plasma testosterone concentrations in adolescent males between 14 and 20 years of age is 0.25 nmol/l or not. [4 marks]

(b) Suppose we have an interest in knowing whether the average plasma testosterone concentrations in adolescent males between 14 and 20 years of age is greater than 0.25 nmol/l. Test this situation. [4 mark]

(c) Suppose we have an interest in knowing whether the average plasma testosterone concentrations in adolescent males between 14 and 20 years of age is less than 0.25 nmol/l. Test this situation. [4 marks]