# Statistics and Compute Mean Sum

949 WordsJul 10, 20124 Pages
Ch.7 # 14 Evolutionary theories often emphasize that humans have adapted to their physical environment. One such theory hypothesizes that people should spontaneously follow a 24-hour cycle of sleeping and waking—even if they are not exposed to the usual pattern of sunlight. To test this notion, eight paid volunteers were placed (individually)b in a room in which there was no light from the outside and no clocks or other indications of time. They could turn the lights no and off as they wished. After a month in the room, each individual tended to develop a steady cycle. Their cycle at the end of the study was as follows: 25, 27, 25, 23, 24, 25, 26, and 25. Using the 5% level of significance, what should we conclude about the theory…show more content…
ni=25 for each group, Xx=5,Xy=4,Xz=6, Xbar=5 SSB=25*(0^2+(-1)^2+1^2)=50 degrees of freedom= k-1=3-1=2, k=number of groups - Compute the sum squares for the error SSE=sum((ni-1)*Si^2)=24*(2+1.5+2.5)=144 degrees of freedom= k(ni-1)=3(25-1)=3*24=72, k=number of groups -- Compute Mean sum of squares for between groups and error MSB=SSB/dof=50/2=25 MSE=SSE/dof=144/72=2 -- compute F statistic= MSB/MSE=25/2=12.5 -- determine the critical F value for alpha 0.05, num dof=2, denom dof=72 Fcritical= 3.12 -- Since Fstatistic &gt; Fcritical then reject Ho and conclude The universities differ in their average time