4. Researchers claim that the average amount of lean mass that can be put on by an experienced athlete (> 21 yrs old) over the course of a year without performance enhancing drugs is less than 2 pounds.  A random sample of 23 experienced athletes followed a strict diet that consisted of 40% protein, 40% carbs, and 20% healthy fats.  At the end of one year, the change in lean mass was recorded for each athlete.  The mean change was 0.9 lbs.  The standard deviation was 0.3 lbs.  Express the claim, the null and alternative hypotheses, and find the test statistic that would be used to test the researcher’s claim.