According to the US Bureau of Labor statistics, the average weekly earning of a production worker in 1997 were $424.5. Suppose a labor researcher wants to test to determine whether this figure is still accurate today .The researcher randomly selected 54 production workers from across the United States and obtained a representative earning statement for one week from each. The resulting sample average is $432.69. Assuming population Standard deviation is 33.90. and a 5% level of significance, To determine whether the mean weekly earnings of the production worker have changed. Required:
To determine whether the mean weekly earnings of the production worker have changed, what would be the value of test statistics?