Wild horse populations on federal lands have been protected since 1971.Since that time,the populations have grown large and need to be managed and kept to a supportable size.Management of the mustang population has been a controversial issue;one common method is periodic removal of the horses.Researchers were curious if a new method would work better.In 1985,12 horses were rounded up and male horses in the group of 12 were treated.The number of foals in each group of 12 horses for 3 years was recorded.Year 1 was prior to treatment,year 2 was the year the treatment was applied,and year 3 was 1 year after treatment.The average number of foals per group along with the standard deviation is given in the table below. The researchers did an ANOVA F test of the data and obtained the following results. For this example,which of the following conclusions is most reasonable?
A)There is moderate evidence that the treatment is effective in reducing herd size for about 1 year,but then the effect appears to wear off.
B)An ANOVA F test is not appropriate for these data.The assumptions needed for the F test to be valid are not all satisfied.
C)The data provide strong evidence that the mean number of foals for the populations represented by the 3 years differ.
D)The data appear to provide little or no evidence that the treatment is effective in reducing herd size.

Question

Wild horse populations on federal lands have been protected since 1971.Since that time,the populations have grown large and need to be managed and kept to a supportable size.Management of the mustang population has been a controversial issue;one common method is periodic removal of the horses.Researchers were curious if a new method would work better.In 1985,12 horses were rounded up and male horses in the group of 12 were treated.The number of foals in each group of 12 horses for 3 years was recorded.Year 1 was prior to treatment,year 2 was the year the treatment was applied,and year 3 was 1 year after treatment.The average number of foals per group along with the standard deviation is given in the table below.  The researchers did an ANOVA F test of the data and obtained the following results.  For this example,which of the following conclusions is most reasonable?
A)There is moderate evidence that the treatment is effective in reducing herd size for about 1 year,but then the effect appears to wear off. 
B)An ANOVA F test is not appropriate for these data.The assumptions needed for the F test to be valid are not all satisfied. 
C)The data provide strong evidence that the mean number of foals for the populations represented by the 3 years differ. 
D)The data appear to provide little or no evidence that the treatment is effective in reducing herd size.

Quizplus · Accepted Answer

The Answer of Wild horse populations on federal lands have been protected since 1971.Since that time,the populations have grown large and need to be managed and kept to a supportable size.Management of the mustang population has been a controversial issue;one common method is periodic removal of the horses.Researchers were curious if a new method would work better.In 1985,12 horses were rounded up and male horses in the group of 12 were treated.The number of foals in each group of 12 horses for 3 years was recorded.Year 1 was prior to treatment,year 2 was the year the treatment was applied,and year 3 was 1 year after treatment.The average number of foals per group along with the standard deviation is given in the table below.  The researchers did an ANOVA F test of the data and obtained the following results.  For this example,which of the following conclusions is most reasonable?
A)There is moderate evidence that the treatment is effective in reducing herd size for about 1 year,but then the effect appears to wear off. 
B)An ANOVA F test is not appropriate for these data.The assumptions needed for the F test to be valid are not all satisfied. 
C)The data provide strong evidence that the mean number of foals for the populations represented by the 3 years differ. 
D)The data appear to provide little or no evidence that the treatment is effective in reducing herd size.

Wild Horse Populations on Federal Lands Have Been Protected Since