Question

can you explain how to fo the mean variance wnd z score and st dev each path

Problem 17-11 The following precedence diagram reflects three time estimates for each activity. Determine: Use Table B1 and Table B2. 9-10-12 5-7-10 8-10-14 11-12-13 11 14-18-26 8-8-8 5-6-7 6-6-6 2 13-13-13 10.5-13-15.5 10 10-12-14 10-11-12 7-10-12 a. The expected completion time for each path and its variance. (Round intermediate calculations to 4 answers to 2 decimal places.) Path 1-2-3-8-11 1-2-4-6-11 1-2-4-7-11 1-2-5-9-10-11 Mean 37.34 43 Var 1.06 5.11 0.81 1.25 Std. Dev 1.03 2.26 0.90 1.12 400 46.83 b. The probability that the project will require more than 49 weeks. (Round intermediate calculations and places.) PT 2 49 wk.) 0.0301 c. The probability that the project can be completed in 46 weeks or less. (Round intermediate calculations decimal places.) PTS 46 wk.)

Answer 1

The expected time for each activity & variance of activity are calculated in the table below each bi O O Activity optimistic Most likely Pessimistič Ite. to +4tm the 3 (tp- boja Hmesto Himec tro) timeltp) 36 172 8 8 8 273 1) 12 13 12 0.1111 25 12 14 12 0.4444 378 g 12 10.167 0,25 244 S 6 7 6 0.1111 4-6 14 18 26 18.667 4 4 +7 13 13 13 13 syg 7 12 9.8333 0.6949 6 +11 8 lo 14 10.333 10.5 13 15.5 13 0.6944 5 10 7.1667 0.6944 9-10 16 1) 12 0.10) 10 111 6 6 6 c 0 1 0 0

path 1 + 27 3 8 11 find mean, vañance, & sd for this path we get, vanance Path 172 Mean 8 1378 8 Yll 12 10, 16.7 7.1667 0.25 0.6944 Total 321, 3333 1056 s. d = 1.056 = 1.027 -1.03 Path 1 / 2 7 4 6 7 11 variance path 1 +2 244 46 6 -Mean 8 6 s.d = 25.11 0.1111 4 = 2.26 18,667 10.333 Total 43 5.11

path 1727 4 7 7 4 11 Vanance Path 142 s.d = 10.806 Mean 8 6 13 13 01111 O 0.89 tu Total 0.6944 0.806 Path 14259 + 10 +11 Mean Varunce s.de Path 1 42 245. 579 9710 lotu 12012 9.833 0.444 0.6944 0.1111 DF 1.118 6 46.8333 Total 1.25 final table & path Mean Narance std. derian 1 72 73 78 411 37.33 1+2+46+1 1427471 40 1+2+5+9+10+11 46.83 5.11 0.81 1.25 1.03 2.26 0.9 1.12

b) The probability that the project will require 49 weelss. than TO NCH, 82) then, १ ll= 46.83 1.12 PC T7,49 ) = (- P(1349) = 1 - PC T-< 49. 49.4) - 1- Pris 49- 46.83 .83 ) 1- PC ZS 1.9375) 1.12 = 1- (1.9375) using std. Normal Table 0.97366 -- P(77,49) = 0,02634 0.03011 Thenfone PCTY, 49 weeles) = 0.030) g The project that the project can be completed in 46 weeks or less. "? P( 7346 week) = P(T-4 <46-4f(Z8 46-46.83 1.12 =P(Z -0,740) = + (-0.411) $0, 2293 - P(75 46 weele) = 0.2293