problem set 3 answers

problem set 3 answers - 7.94 = 24 minutes, = 7 minutes, and...

Info iconThis preview shows pages 1–5. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: 7.94 = 24 minutes, = 7 minutes, and n = 100 7 x = = 24 minutes and x = = = .7 minutes n 100 The sampling distribution of x is approximately normal because n >30 7.96 = 24 minutes, = 7 minutes, and n = 100 7 x = = 24 minutes and x = n = 100 = .7 minutes (x - ) (22 - 24) = = -2.86 x .7 a. F or x = 22 : z= P (x < 22) = P (z < -2.86) = .0021 b. F or F or x = 23 : x = 26 : z= (x - ) (23 - 24) = = -1.43 x .7 (x - ) (26 - 24) = = 2.86 x .7 z= P (23 < x < 26) = P (-1.43 < z < 2.86) = P (z < 2.86)-P (z < -1.43) = .9979-.0764 = .9215 c. P (x within 1 minute of ) = P (23 x 25) F or F or x = 23 : x = 25 : z= z= (x - ) (23 - 24) = = -1.43 x .7 (x - ) (25 - 24) = = 1.43 x .7 P (23 x 25) = P (-1.43 z 1.43) = P (z 1.43)-P (z -1.43) = .9236-.0764 = .8472 d. P (x greater than by 2 minutes or more) = P (x 26) F or x = 26 : z= (x - ) (26 - 24) = = 2.86 x .7 1 P (x 26) = P (z 2.86) = 1 - P (z 2.86) = 1 - .99979 = .0021 7.99 p = .88, q = 1 - p = 1 - .88 = .12, and n = 80 r r pq (.88)(.12) p = p = .88, and p = = = .03633180 n 80 np = (80) (.88) = 70.4 > 5, nq = (80)(.12) = 9.6 > 5 Since np and nq are both greater thatn 5, the sampling distribution of p is approximately normal. b 7.109 = 160 pounds, = 25 pounds, and n = 35 25 x = = 160 pounds and x = = = 4.22577127 pounds n 35 Since n > 30, x is approximately normally distributed. P (sum of 35 weights exceeds 6000 pounds) = P (mean weight exceeds 6000/35) = P (x > 171.43) (x - ) (171.43 - 160) = = 2.70 x 4.22577127 F or x = 171.43 : z= P (x > 171.43) = P (z > 2.70) = 1 - P (z 2.70) = 1 - .9965 = .0035 2 ...
View Full Document

This note was uploaded on 03/10/2008 for the course ECON 41 taught by Professor Guggenberger during the Spring '07 term at UCLA.

Page1 / 5

problem set 3 answers - 7.94 = 24 minutes, = 7 minutes, and...

This preview shows document pages 1 - 5. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online