Question

Twelve different video games showing substance use were observed and the duration of times of game play​ (in seconds) are listed below. The design of the study justifies the assumption that the sample can be treated as a simple random sample. Use the sample data to construct a 90​% confidence interval estimate of σ​, the standard deviation of the duration times of game play. Assume that this sample was obtained from a population with a normal distribution. 4900 4545 4123 4397 4081 4949 3833 4376 4477 4617 4836 4705

Answer 1

(X-x) 413.417 58.417 363.583 89.583 -405.583 462.417 -653.583 110.583 9.583 130.417 349.417 218.417 (x-x)2 170913.3403 3412.5069 132192.8403 8025.1736 164497.8403 213829.1736 427171.1736 12228.6736 91.8403 17008.5069 122092.0069 47705.8403 1319168.9167 119924.4.5 346.30 S.No 1 4900.00 4545.00 4123.00 4397.00 4081.00 4949.00 3833.00 4376.00 4477.00 4617.00 4836.00 4705.00 53839 2 4 10 12 4486.5833 s-(x-x)/n-1)- here n 12 119924.4.5 Critical value for 11 degree of freedom and 90 % CI are as follows 4.575 0.05 19.675 0.95 Variance Cl- (n-1)s /x Variance C 67047.975 288342.933 Std deviation C 258.936 536.976

from above 90% confidence interval of std deviation =258.94 ; 536.98