Question

Source: Time magazine, Oct. 2006. Work Interruptions Research by Steelcase found the average worker get interrupted every 11 minutes and 23 minutes to get back on task. From a random sample of 200 11 minutes by email, texts, alerts, etc. Find the 90% con- fidence interval of the population proportion of workers who are interrupted every 11 minutes. takes workers, 168 said they are interrupted every

Answer 1

1)

168 sample size sample proportion 200.0 p std error Se 0.0259 for 90 % CI value of z- margin of error E-z*std error lower confidence bound-sample proportion-margin of error Upper confidence bound-sample proportion+margin of error 1.645 0.0426 0.883

90% confidence interval for proportion =0.797 ; 0.883

2)

(Х-х) -23.214 -23.214 -33.214 -13.214 31.786 16.786 -3.214 23.214 -3.214 3.214 36.786 -13.214 36.786 16.786 (Х-х) S.No 220.000 220.000 210.000 230.000 275.000 260.000 240.000 220.000 240.000 240.000 280.000 230.000 280.000 260.000 1 538.9031 538.9031 1103.1888 174.6173 1010.3316 281.7602 10.3316 538.9031 10.3316 10.3316 1353.1888 174.6173 1353.1888 281.7602 7380.3571 567.720 2 4. 10 12 13 14 243.214 s'-(x-)/(n-1- here n 567.720 S- Critical value for 13 degree of freedom and 95 % CI are as follows 5.009 0.025 24.736 0.975 (n-1)s /x Variance Cに (n-1)s/xu Variance CI 298.365 1473.419 Std deviation CI 17.273 38.385

95% CI for std deviation =17.273 to 38.385