help me to answer q 5

Question 5: Suggested Time - 30 minutes (CO2/PO2 - 10%) A job in an insurance office involves telephone conversation with policy holders. A time study has been conducted by En Adam, the office manager to estimate the telephone conversation time by the insurance officer. Based on the observation shown in the Table 4, the manager proposes to develop a time standard for the whole conversation. Table 4 Job Observed time (minutes) element A 2.5 2.8 2.6 2.4 0.86 2.5 3.0 2.4 2.2 2.3 2.1 2.5 D 0.6 2.5 2.8 Disregard - interruption by manager Disregard - policyholder cancelled the call 3.8 2.8 2.8 2.4 2.4 0.56 2.7 4.0 Performance rating 95% 70% 110% 80% 2.9 i) By assuming the total allowance factor is 15%, compute the standard time for the job. [CO2/PO2/C3] (10 marks) ii) En. Adam also did 300 works sampling observation of one of his staff, Abu Abu worked a 40-hour in a week. The sample also showed that Abu was busy working (consulting with policyholders) during 250 observations. a) Find the percentage of time Abu was working. b) Determine the sample size if a confidence level of 96.6%, and if 3% is an acceptable error c) Was the sample size adequate? [CO2/PO2/C3]