Step 1.
Set up hypotheses and determine level of significance
Ho
Ha: Should the alternative hypothesis be upper-tailed, lower-tailed, or two-tailed?
Step 2.
Select the appropriate test statistic
Insert Specific Formula (Consider sample size to determine Z-score or T-distribution)
Step 3.
Set up decision rule
Do NOT use your level of significance as a part of your decision rule. Be sure to use
only the critical values found in your appendices. Critical values are based upon the type
of test used, your sample size or degrees of freedom, your alternative hypothesis
(upper-tailed, lower-tailed, or two-tailed), and your level of significance.
When using a two-tailed test, be sure to include both positive and negative values of the
critical value.
Be sure to include the equal sign. For example, "Reject Ho if Zā„ 1.960."
Step 4.
Compute the test statistic.
Please show all computations. If you do not show your computations, you will not
receive credit, even if your test statistic is correct.
Step 5.
Conclusion
There should be two parts to your conclusion-1) Your decision to either reject or fail to
reject the null hypothesis; and 2) You conclusion. Please state both portions. If we reject
the null hypothesis for an upper-tailed test, we can simply say "Reject the null hypothesis
because XXX value is greater than YYY value...
Your conclusion statement should also reflect the null and alternative hypotheses. For
example, "We have statistically significant evidence to indicate a difference in...".
PROBLEM XX. A randomized clinical trial is conducted to examine the impact of an experimental drug
designed to lessen the menstrual cycle length, compared to a placebo. The data below were collected at
the end of the 6 month study.
Mean Cycle Length (Days)
Standard Deviation
Experimental (n = 40)
27.7
2.1
Placebo (n = 40)
28.6
2.9
At a .05 level of significance, does the data support the hypothesis that the experimental drug lessens the
length of a female's menstrual cycle?
1. Set Up Hypothesis and Determine Level of Significance
2. Select the Appropriate Test Statistic
3. Set Up the Decision Rule
4. Compute the Test Statistic
5. Decision and Conclusion