A study plans to have a sample of obese adults follow a proposed low-carbohydrate diet for three months. The diet imposes limited eating of starches (such as bread and pasta) and sweets, but otherwise no limit on calorie intake. Consider the hypothesis,
The population mean of the values of weight change (= weight at start of study - weight at end of study) is a positive number.
a. Is this a null or an alternative hypothesis? Explain your reasoning.
b. Define a relevant parameter, and express the hypothesis that the diet has no effect in terms of that parameter. Is it a null or alternative hypothesis?