Question

Toxaphene is an insecticide that has been identitied as a pcilutant in the Great Lakes ecosystem. To investigate the etfect of toxaphene exposure on animals, proups of rats were given toxaphene in their diet. A study reports weight gains (in grams) tor rats given a low dase (4 ppm) and tor contro rats whose di t did not include the insectic de The sample standard deviation or 22 cmalc control rats was 31 q and for 1りtemale ov ose rats was 57 g Docs this data suggest that there is more variability n o dose weight gans than n contro o ght gains? Assuming normality, carry out a test of hypotheses at significance level 0.05 state the relevant hypotheses.use σ1 for low-doe treatment and σ2 for control condition.) Calculate the test statistic. (Round your answer to two decimal places.) what can ba sald about the Pvalue for tha test? o p-value 0.100 0.050 P-vlue 0.100 0.010 < Pvalue 0.050 0.001 cP-valuc c 0.010 o P-value< 0.001 State the condusion in the problem context. o Fail to reject Ho. The data does not suggest that there is more variabiity in the low-dose weight gains than in control weight gains 0 fail to re」ect HD. The data suggests that there is more variability in the low-dose weght gains than in contrul weight gains. o Rejoct Ho. The data does not suagest that there is more variability in the low-dosc weight qains than in control weight gains. o Reject Ho. The data suggests that there is more variability in the low-dose weight gains than in control weight gains

Answer 1

The statistical software output for this problem is:

Two sample variance summary hypothesis test: σ12 : Variance of population 1 σ22 : Variance of population 2 σ12/σ22 : Ratio of two variances Ho : σ12/o22-1 Hypothesis test results: Ratio Num. DF Den. DF Sample Ratio F-Stat P-value 21 3.3808533 3.3808533 0.0044 |σ'/o22| 18

Hence,

Hypotheses: Option D is correct.

Test statistic: f = 3.38

0.001 < p - value < 0.010; Option D is correct.

Conclusion: Option D is correct.