A researcher noticed that for streams along the east coast t

A researcher noticed that, for streams along the east coast, the amount of money spent on restoration and the number of distinct fish populations present appeared to have a negative correlation. Which of the following is most likely to be the reasoning he used to decide that a lurking variable must be present? Select one: A. The data would be wrong otherwise since correlations can?t be negative. B. He expected a positive correlation, so obviously something must be wrong. C. More money spent on restoration likely indicates a stream of lesser quality. Hence, there may be fewer fish present. D. None of the above Tail-feather length in birds is sometimes a sexually dimorphic trait. That is, the trait differs substantially for males and for females. Researchers studied the relationship between weight (x) and tail-feather length (in a sample of 5 wild male long tailed finches. Here are the data: The percent of variations in tail-feather length that can be explained by weight among male long tailed finches is approximately Select one: A. 94% B. 89% C. 62%. D.79%.

Solution

question 19. answer is option D) 79%

because in the regression of tail length(Y) on weight(X) the value of coefficient of variation is 78.9%

question 18.   answer is option C) it is the most likely reason