(a) How many standard deviations (of Xˉ ) below the null value is xˉ=72.3 ? (Round your answer to two decimal places.) ₹ standard deviations (b) If xˉ=72.3, what is the conclusion using α=0.004? Calculate the test statistic and determine the P-value. (Round your test statistic to two decimal places and your P-value to four decimal places.) z= P-value =