i can’t find the explanation in the book: A test statistic is best defined as: A. the difference between the critical value and the hypothesized value B. the difference between a point estimate of a population parameter and its hypothesized value C. an estimate of the value of the parameter in question based on a smaple D. the value or values that define the regions from rejecting or failing to reject the null hypothesis it says the answer is B … why??

that is correct. Test statistic is the diference between point estimate of population parameter and its hypothesized value , divided by sample standard error.

Yes, I was caught up by this question as well. I looked at the CFAI definition and was still not understanding it. I think its the wording that is bad.