Question

Quality of oil is measured in API gravity degrees. The higher the degree of API, the higher the quality. The data is produced by an expert in the field who believes that there is a relationship between quality (x) and price per barrel (y). The data is listed below. Which of the following is incorrect?

A) a 95% prediction interval of the oil price per barrel for an API degree of 35 is (12.4680, 13.0682)

B) A 95% confidence interval for the average oil price per barrel for an API degree of 35 is (12.6876, 12.8486)

C) The regression equation is: Oil degrees API = -88.9 + 9.71 Price per barrel (in $)

D) The confidence interval estimate of the expected value of y is narrower than the prediction interval for the same given value of x (10 years) and some confidence level. This is because there is less error in estimating a mean value as opposed to predicting an individual

Oil degrees API	Price per barrel (in $)
27.0	12.02
28.5	12.04
30.8	12.32
31.3	12.27
31.9	12.49
34.5	12.70
34.0	12.80
34.7 37.0 41.0 41.0 38.8 39.3	13.00 13.00 13.17 13.19 13.22 13.27

Answer 1