Question the construction of the tminus−statistic for a oneminus− and a twominus−sided hypothesis a. uses plus or minus±1.96 for the twominus−sided test, but only +1.96 for the oneminus−sided test. b. is different since the critical value must be 1.645 for the oneminus−sided hypothesis, but 1.96 for the twominus−sided hypothesis (using a 5% probability for the type i error). c. depends on the critical value from the appropriate distribution. d. is the same.