Question

During part of a recent season, pitcher Ubaldo Jimenez threw 2825 pitches. Of these, 1912 were fastballs, 228 were curve-balls, 457 were sliders, and the remaining were change-ups. Round all answers to 4 decimal places. a. What is the probability that Jimenez threw a fastball? b. What is the probability that Jimenez threw a curve-ball or a slider? c. What is the probability that the ball thrown was not a change-up?

Answer 1

Solution:

Given:

Pitches	Frequency
Fastballs	1912
Curve-balls	228
Sliders	457
Change-ups	228
	N= 2825

Part a) Find:

P( Jimenez threw a fastball ) =.............?

P( Jimenez threw a fastball ) = Number of threw are Fastballs / N

P( Jimenez threw a fastball ) = 1912 / 2825

P( Jimenez threw a fastball ) = 0.6768

Part b) Find:

P( Jimenez threw a curve ball or a slider) = ............?

P( Jimenez threw a curve ball or a slider) =P( Jimenez threw a curve ball ) + P(Jimenez threw a slider)  

P(Jimenez threw a curve ball or a slider) = [ Number of threw are curve ball / N ] + [ Number of threw are slider / N ]

P(Jimenez threw a curve ball or a slider) = 228 / 2825 + 457 / 2825

P(Jimenez threw a curve ball or a slider) = ( 228+457) / 2825

P(Jimenez threw a curve ball or a slider) = 685 / 2825

P(Jimenez threw a curve ball or a slider) = 0.2425

Part c) Find:

P( Ball thrown was not change-up) = ........?

P( Ball thrown was not change-up) = 1 - P( Ball thrown was change-up)

P( Ball thrown was not change-up) = 1 -  Number of threw are change up / N

P( Ball thrown was not change-up) = 1 - 228 /2825

P( Ball thrown was not change-up) = 1 - 0.0807

P( Ball thrown was not change-up) = 0.9193