State quantitatively the null hypothesis H0 and the alternative hypothesis Ha for the following situations and describe the type I and type II errors. If these hypotheses were to be tested statistically, comment on whether a one- or two-tailed test would be involved for each case.
(a) The mean values for Ca determinations by an ion-selective electrode method and by an EDTA titration differ substantially.
(b) Results show that the batch-to-batch variation in the impurity content of Brand X acetonitrile is lower than Brand Y acetonitrile.