Cortisol is a hormone that plays an important role in mediating stress. There is
ID: 3227485 • Letter: C
Question
Cortisol is a hormone that plays an important role in mediating stress. There is growing awareness that expo-sure of outdoor workers to pollutants may impact Cortisol levels. The article "Plasma Cortisol Concentration and Lifestyle in a Population of Outdoor Workers" (Intl. J. of Envir. Health Res., 2011: 62-71) reported on a study involving three groups of police officers: (1) traffic police (TP), (2) drivers (D), and (3) other duties (0). Here is summary data on Cortisol concentration (ng/ml) for a subset of the officers who neither drank nor smoked. Assuming that the standard assumptions for one-way ANOVA are satisfied, carry out a test at significance level .05 to decide whether true average cortisol concentration is different for the three groups.Explanation / Answer
from above
as p vlaue is less then 0.05 level we reject that all mean are same and conclude of having sufficient evidence that at least two of above group has diffferent means
i ni Xi Si^2 ni*(Xi-mean)^2 (n1-1)*Si^2 1 47 174.7 2590.81 6655.670 119177.26 2 36 160.2 1383.84 243.360 48434.4 3 50 153.5 2106.81 4324.500 103233.69 mean 162.800 11223.530 270845.350 MSG MSE Source of variation SS df MS F P value F crit Between groups 11223.530 2 5611.765 60.374 0.00000 3.065839 with in groups 270845.350 130 92.950 total 282068.880 132