Question

Reserve Problems Chapter 10 Section 1 Problem 3 The time delay is measured for a city street. Variability in this value is estimated as (for time in minutes) by experience. Traffic signs and lights were recently altered to facilitate traffic and reduce delays. Delay times in minutes for a random car sample before and after the rearrangement are shown below. Before 7.2 7.1 7.1 7.0 7.4 7.1 6.8 6.5 7.1 7.2 7.5 7.1 After 6.2 6.6 6.2 6.1 6.8 5.8 5.8 5.7 6.1 6.0 7.1 6.9 Assume that the time delay variability is unaffected by the traffic signs change. If the difference in the time delay is 1 minute or less, we would like to detect it. (a) Formulate and test an appropriate hypothesis using . What is your conclusions? Find the P-value. 1) The parameter of interest is the difference in the mean time delay before and after the rearrangement, . 2)   Enter your answer; H0: mu1-mu2 = . 3)   Enter your answer; H1: mu1-mu2 < . Find the test statistic. Round your answers to three decimal places (e.g. 98.765). Enter your answer; z0 Enter your answer; P-value (b) Find a 90% confidence interval for the difference in the mean time delay. Round your answers to three decimal places (e.g. 98.765). We are 90% confident that the difference in the mean time delay lies between Enter your answer; confidence interval, lower bound Enter your answer; confidence interval, upper bound

Reserve Problems Chapter 10 Section 1 Problem 3 The time delay is measured for a city street. Variability in this value is estimated as o = 0.3 (for time in minutes) by experience. Traffic signs and lights were recently altered to facilitate traffic and reduce delays. Delay times in minutes for a random car sample before and after the rearrangement are shown below. Before 7.2 7.1 7.1 7.0 7.4 7.1 6.8 6.5 7.1 7.2 7.5 7.1 After 6.2 6.6 6.2 6.1 6.8 5.8 5.8 5.7 6.1 6.0 7.16.9 Assume that the time delay variability is unaffected by the traffic signs change. If the difference in the time delay is 1 minute or less, we would like to detect it. (a) Formulate and test an appropriate hypothesis using a = 0.1. What is your conclusions? Find the P-value. 1) The parameter of interest is the difference in the mean time delay before and after the rearrangement, Hi - U2. 2) Ho : Mi - U2 = 3) H: Hi-u2 < Find the test statistic. Round your answers to three decimal places (e.g. 98.765). Zo P – value = (b) Find a 90% confidence interval for the difference in the mean time delay. Round your answers to three decimal places (e.g. 98.765). We are 90% confident that the difference in the mean time delay lies between <Mi - U2 >

Answer 1

Answett For the given dota loptours Before Altog Y2 7,= Erlin lott 2.2+2.1 + 1.58 - 7.092 - 12 +6:9 X2= 6-2+6.6+ 12 - 6.275 =12 at 3753 12 a), e- - ll2 = Ho 7.092-6:275 = 0-817 My-l2=0.817 2) Hoito-esq-1 37 Hii U, -uzi Test Statistics (2) -72) -(4-42) ha C-03 d-01

(7.092-6.275) -1 0.3 12 0817-1 0.37 0.4082 -0.183 012246 [20= -1.4944 P-value0.0681 0.0681 0.1 Reject Nun hypothesis we 90%, CI 0.10 in the mean =720.10=164s For the difference 90%c I time deiay is che ha =) (71-72) = (Zalo 0.817 + C1.645x0.3 70.4082) 0.817 +0.2014

= 10.6156, 1.0184)~ (0.616, 101?) Le confident 90/ we are hoop gult the difference 6.6161 0.616) < eli-lla lies between