# Help

• Nov 1st 2009, 02:31 AM
foreg0ne
Help
CAn some please check if the answers i have put are right and help me with the rest. Gotta get through this

An experiment was conducted to evaluate the effectiveness of a treatment for tapeworm in the stomachs of sheep. A random sample of 23 worm-infected lambs of approximately the same age and health was randomly divided into two independent groups. Twelve of the lambs were injected with the drug and the remaining eleven were left untreated. After a 6-month period, the lambs were slaughtered and the worm counts were recorded for each sheep.
We assume the data follow a normal distibution. We also assume the equality of the two
population variances in this problem. The following is a partial Minitab output from applying a two-sample t procedure for these data, where C1 contains the worm counts data for the drug-treated sheep and C2 for untreated sheep.

+++++++++++++++++++++++++++++++++
Two-sample T for C1 vs C2
N Mean StDev
C1 12 26.6 14.4
C2 11 39.7 14.5
++++++++++++++++++++++++++++++++++

(a) Calculate the pooled sample standard deviation sp.
Using the sp formula

= 14.45

(b) Test whether the mean worm counts μ1 for the drug-treated group is less than the mean μ2
for the untreated group. Use significance level 0.05 and the equal variance assumption. List
H0 and Ha, the test statistic, the rejection region, the range of the p-value and the conclusion.

H0: mu 1 < mu 2 vs Ha: mu 1 ≥ mu 2

Test statistic -2.17

(c) Find a 99% confidence interval for μ1 − μ2, the difference between the population mean worm counts for the drug-treated group and that for the untreated group. Use the equal variance assumption.
• Dec 20th 2012, 05:39 AM
estatistics
Re: Help
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