A welldesigned and safe workplace can contribute greatly to

A well-designed and safe workplace can contribute greatly to increased productivity. It is especially important that workers not be asked to perform tasks, such as lifting, that exceed their capabilities. The accompanying data on maximum weight of lift(MAWL, in kg) for a frequency of four lifts/min was reported in the article \"The Effects of Speed, Frequency, and Load on Measured Hand Forces for a Floor-to-Knuckle random Lifting Task\" (Ergonomics, 1992: 833-843); were randomly selected from the population of healthy males ages 18-30. Assuming that MAWL is normally distributed, does the data suggest that the population mean MAWL exceeds 25? Carry out a test using a significance level of .05.

Solution

Formulating the null and alternative hypotheses,              
              
Ho:   u   <=   25  
Ha:    u   >   25  
              
As we can see, this is a    right   tailed test.      
              
Thus, getting the critical t,              
df = n - 1 =    4          
tcrit =    +   2.131846786      
              
Getting the test statistic, as              
              
X = sample mean =    27.54          
uo = hypothesized mean =    25          
n = sample size =    5          
s = standard deviation =    5.470648956          
              
Thus, t = (X - uo) * sqrt(n) / s =    1.038197243          
              
Also, the p value is              
              
p =    0.178906737          
              
As |t| < 2.1318, and P > 0.05, we   FAIL TO REJECT THE NULL HYPOTHESIS.          

Thus, there is no sufficient evidence at 0.05 level that the population mean MAWL exceeds 25. [CONCLUSION]