Question

A baseball​ pitcher's most popular pitch is a​ four-seam fastball. The data below represent the pitch speed​ (in miles per​ hour) for a random sample of 15 of his​ four-seam fastball pitches.

85.5, 86.8, 93.1, 93.6, 88.7, 92.8, 86.4, 93.7, 89.9, 91.2, 86.7, 93.9, 85.4, 87.4, 90.6

(a)

Using the correlation coefficient of the normal probability​ plot, is it reasonable to conclude that the population is normally​ distributed?

Since the absolute value of the correlation coefficient between the expected​ z-scores and the ordered observed​ data, ____, ____ (exceeds/ does not exceed) the critical value ___, it (is/ is not) reasonable to conclude that the data come from a population that is normally distributed. (Round three decimal places)

(b) Construct and interpret a​ 95% confidence interval for the mean pitch speed of the​ pitcher's four-seam fastball.

One can 95% confident that the mean pitch speed of the pitcher's four-seam fastball is between ___ and ___ miles per hour.

One can 90% confident that the mean pitch speed of the pitcher's four-seam fastball is between ___ and ___ miles per hour.

One can 99% confident that the mean pitch speed of the pitcher's four-seam fastball is between ___ and ___ miles per hour.  

Answer 1