Company officials were concerned regarding the length of time a specific drug product retained its potency. A random sample of n1 = 10 bottles of product was drawn from production line and analyzed for potency. A second sample of n2 = 10 bottles was obtained and stored in regulated environment for one year. Let µ1 denote the mean potency for all bottles coming off production line and let µ2 denote the mean potency for all bottles retained for period of 1 year. Suppose that population variances are unknown but equal. Is the potency for fresh drugs different from that for stored drugs? Use alpha = .05 Potency Reading for the two samples:
Fresh: 10.2 10.5 10.3 10.8 9.8 10.6 10.7 10.2 10 10.6
Stored: 9.8 9.7 9.6 9.5 10.1 9.6 10.2 9.8 10.1 9.
n. In this problem you were asked to perform a pooled variance t-test. Were we justified in assuming equal variances? Conduct a hypothesis test ( F test) to check for equality of variances.
1. State the null and alternate hypotheses Ho:__________ Ha:_____
2. State the F test statistic _________
3. The numerator and denominator deg of freedom______,______
4. State the critical value obtained from the F table ____________ (F table is posted under Lectures on Blackboard for your convenience.)
5. State your conclusion of this F test. Were we justified in conducting a pooled variance t test?