The Z calculated value (2.35) is greater than the Z critical value (1.96) and thus we reject the null hypothesis. There is sufficient evidence at 5% level of significance to conclude that there is a significant difference between the average annual wage of an advertising managers and the average annual wage of an auditing managers [p-value of the two tail test statistic (Z = 2.35) is 2 x 0.0094 = 0.0188, which is less than = 0.05, implying that we reject the null hypothesis]
Question: Why use the negative Z value(-2.35) to find the P value instead of the 2.35?