The average weekly earnings of aproduction worker in 2000 were AUD421. Suppose a labor researcher wants to test todetermine whether this figure is still accurate today.

The researcher randomly selects56production workers and obtains a representativeearnings statement for one week from each. The resulting sample average is AUD432.2.

Assuming a population standard deviation of AUD34.0and a 5% level of significance,determine whether the mean weekly earnings of a production worker have changed.

Determine the critical value z_cand z score value z based on the sample data.

The critical value z_c=

The z score value z based on the sample data ==