Mayor Jonathan (Johnny) Johnson of Graft City is running for reelection. At a big rally in the city park, volunteers will assemble signs reading “A vote for Johnny is a vote for Graft” to be placed on front lawns and city property. To ensure that the rally will go smoothly, the mayor directs the public works department to conduct a preliminary time study to estimate the rate of work and number of city workers that will be needed to make signs during the rally. The results (in seconds) are shown in Figure H.5.

Figure H.5

a. Because of the chaos and uncontrolled environment at the city park rally, allowances will be 25 percent of the normal time. Determine the normal time for the cycle and the standard time.
b. The mayor does not like to leave things to chance. Suppose that he wants 99 percent confidence that each work element’s average time from the study is within ±5 percent of the true average. Did the public works department make enough observations? If not, how many more should be made?

Transcribed Image Text:

Observer: public works employee Operation: Yard sign assembly Date: 9/27 Observations 9. Work Element 2 3 4 10 RF 1. Get stake and sign 70 107 207 39 142 181 254 282 312 1.0 1.05 2. Put glue on stake 75 14 46 112 151 185 214 259 285 316 1.0 0.8 3. Place sign, four staples 0.9 270 25 60 90 126 168 196 236 298 338 1.0 4. Check assem., set aside 97 132 176 276 343 30 64 199 245 303 1.0 1.2 Normal time for cycle: seconds per piece 25% Allowances (% of total time): Standard time: