(2 points) Before surgical removal of a diseased parathyroid gland, two tests are often performed: the standard intact test and the turbo test. Both tests measure parathyroid hormone (PTH, in ng/l), but the turbo test is very expensive. Researchers obtained data from both tests in a sample of 48 patients to predict turbo test results (y) from standard intact test results (x). The data ranged from roughly 0 to 500 ng/l, and a scatterplot showed a clear linear relationship. The published findings are summarized exactly as follows: y = 1.08x - 4.36 (r = 0.97; n = 48)
Roughly what percent of the variation in turbo test results can be explained by this regression model?
A. 94%
B. 98.5%
C. 97%
D. It is not possible to answer with the information provided.
For a PTH level of x = 1000 ng/l with the standard intact test, what is the predicted PTH level with the turbo test?
A. 1075.64 ng/l
B. 970 ng/l
C. 1036.4 ng/l
D. Cannot be predicted accurately because it would be extrapolation