in question 5

1. Why Z(0.001) is negative 2.33 but not positive 2.33?
2. how to compare Z calculate (first Z in question) and Z table (second Z in question ) if one is positive and another one is negative.

Thanks a lot in advance.

5 In a survey of the number of employees at medium size retailers, 160 companies were selected at random and the following summary statistics obtained: Variable N Mean Median Tr Mean StDev SE Mean Employee 160 212 . 32 209.59 212 . 04 42 . 98 3. 40 (a) Test the hypothesis that the average number of employees is 220 against the one sided alternative that it is less than this. Assume a 1% significance level. Z = (212.32 - 220) /3. 40 = -2.26 Z (0 . 01) = -2.33 Do not reject HO at 18 level (4 marks)