Example of 1-Sample Wilcoxon

A chemist for a pharmaceutical company wants to determine whether the median reaction time for a newly developed antacid is less than 12 minutes. The chemist measures the reaction time for 16 samples of the antacid.

The chemist performs a 1-sample Wilcoxon test to determine whether the median reaction time is less than 12 minutes.

  1. Open the sample data, AntacidReactionTime.MTW.
  2. Open the 1-Sample Wilcoxon dialog box.
    • Mac: Statistics > 1-Sample Inference > Wilcoxon
    • PC: STATISTICS > One Sample > Wilcoxon
  3. In Sample, enter Time.
  4. Select Perform hypothesis test.
  5. In Hypothesized median, enter 12.
  6. Select Options.
  7. From Alternative hypothesis, select Median < hypothesized value.
  8. Click OK.

Interpret the results

The null hypothesis states that the median reaction time is 12 minutes. Because the p-value is approximately 0.23, which is greater than the significance level of 0.05, the chemist fails to reject the null hypothesis and cannot conclude that the median reaction time is less than 12 minutes.

Method
η: median of Time
Descriptive Statistics
N
Median
Achieved Confidence
Test
N for Test
Wilcoxon Statistic
P-Value
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