Question

1. A drug company was concerned about the length of time a particular drug retained its potency. A random sample (Sample1 of 10 bottles of the product was drawn from current production and analyzed for potency, A second sample (Sample 2, inde- pendent with first sample) was obtained, stored for year, and then analyzed. The measurements obtained are as follows: Sample 1 10.6 10.2 10.5 10.3 10.8 9.8 10.6 10.7 10.2 10.0 9.9 9.8 9,6 10. 10.2 10 9.7 9.5 9.6 9.8 aln Perform a test to determine whether the potency level is significantly different for the drug after being stored for a year at a-.05 (a) Set up the appropriate Ho and Ha (b) Caleulate the test statistic. (c) Find the P-value and make your conclusion

Answer 1

Step 1: In EXCEL, Select Add-Ins> Mega Stat> Hypothesis Tests Step 2: Choose Compare Two Independent Groups Step 3: Choose Data Input Step 4: In Group 1, enter the column of Sample 1 Step 5: In Group 2, enter the column of Sample 2 Step 6: Enter 0 Under Hypothesized difference Step 7: Check t-test (unequal variance), enter Confidence level as 95.0 Step 8: Choose not equal in alternative Step 9: Click OK. Excel add-in (Mega Stat) output Hypothesis Test: Independent Groups (t-test, unequal variance) Sample 1 Sample 2 10.370 9.830mean 0.3230.241 std. dev 10 10 n 16 df 0.5400 difference (Sample 1 Sample 2) 0.1275 standard error of difference 0 hypothesized difference 4.24 t 0006 p-value (two-tailed)

Thus the value of test statistic is 4.24 The p-value is 0.0006. Conclusion: Use a significance level, α-0.05 Here, p-Value is 0.0006, which is lesser than the value of α-0.05. That is, p-value(-0.0006) < α(-0.05) Therefore, by the rejection rule, reject the null hypothesis H Interpretation There is sufficient evidence at level of significance α-005 That is, the potency level is significantly different for the drug after being stored for a year