Case study stats

2

Hypothesis Testing

Step 1: Setting the hypothesis; both null and alternative

Here we are testing if the revenue average increased after increasing the working days.

Step 2: Confirming the given information

Our sample is 36 working days. Therefore, n = 36

Mean and standard deviation should be computed from the given data

Comment by Tem Bugarin: Great. Easier way to get these parameters is to use excel’s descriptive statistics.

Therefore, Comment by Tem Bugarin: yes

Step 3: Choosing the test statistic

The test statistic based on the claim and the sample size that will fit this test is Z-test Comment by Tem Bugarin: yes

This test is chosen because sample size is greater than 30. Comment by Tem Bugarin: Great

Step 4: Computations using the chosen test statistics

Step 5: Finding the Critical Value

Testing the claim at 5% significance level

Critical value from (normal distribution table) at , is 1.65 Comment by Tem Bugarin: yes

Step 6: Comparing the Computed value to the Critical value

Our computed value is 0.5787 and it is less than the critical value, 1.65

Step 7: Interpretation

1.65

From the bell shape, the computed value falls within the rejection region and therefore we reject the null hypothesis. Comment by Tem Bugarin: You have the correct decsion but the wrong reason. See attached rubric

Step 8: Conclusion

Since we have enough statistical evidence to reject null hypothesis, we conclude that increasing the working days had a significant impact on the organization’s average revenue in thousands.