Acandy factory that produces chocolate bars claims each bar weighs 50 grams, at least that is what is printed on the label. of course, there is bound to be a little variation. an inspector randomly chooses 9 bars from one day's output of 4000 bars. the average weight of the 9 bars is only 47 grams. the inspector wishes to test the null hypothesis that the factory is doing what it is supposed to on this day against the alternative that the company is cheating the consumer. assume that the weights of all the candy bars that are produced follow the normal curve with a sd of 3 grams. a. which significance test should be used?