An analyst calculates that the mean of a sample of 200 observations is 5. The analyst wantsTo determine whether the calculated mean, which has a standard error of the sample statistic of 1, is significantly different from 7 at the 5% level of significance. Which of the following statements isleast accurate?:
选项：

A: The alternative hypothesis would be H: mean>7.
B: The null hypothesis would be: Ht: mean = 7.The mean observation is significantly different from 7, because the calculated i
C:Statistic is less than the critical Z-statistic.