Question

Listed below are amounts of strontium-90 (in millibecquerels, or mBq, per gram of calcium) in a simple random sample of baby teeth obtained from State X residents and State Y residents born after 1979. Use a 0.10 significance level to test the claim that the median amount of strontium-90 from State X residents is the same as the median from State Y residents. Use the Wilcoxon rank-sum test. State X State Y 153 147 149 130 155 128 137 142 133 136 167 127 148 146 124 137 161 136 138161 142 | 138 132 | 139 Identify the null and alternative hypotheses for this test Ho: The median amount of strontium-90 from State X residents is the same as the median from State Y residents. Hy: The median amount of strontium-90 from State X residents is different from the median from State Y residents. Identify the P-value. (Round to three decimal places as needed.)

Answer 1

Excel add-in (PH Stat) procedure: Step 1: In EXCEL, Select Add-Ins > PH Stat > Two-Sample Tests (Un summarized Data). Step 2: Choose Wilcoxon Rank Sum Test. Step 3: In Data enter 0 Under Hypothesized Difference Step 4: Enter 0.10 Under Level of Significance. Step 5: Enter Al:A13 Under Population 1 Sample Cell Range. Step 6: Enter B1:B13 Under Population 2 Sample Cell Range. Step 7: Check First cells in both ranges contain label. Step 8: Choose Two-Tail Test Under Test Options. Step 9: Click OK. Excel add-in (PH Stat) output:

Wilcoxon Rank Sum Test Data Level of significance Population 1 Sample Sample Size Sum of Ranks Population 2 Sample Sample Size Sum of Ranks Intermediate Calculations Total Sample Sizen T1 Test Statistic 203 T1 Mean Standard Error of Ti 17.3205 Z Test Statistic 3.0599564 Two-Tail Test Lower Critical Value - 1.6449 Upper Critical Value 1.6449 p-Value 0.0022 Reject the null hypothesis P-value = 0.002.