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As part of a risk assessment study a nurse was hired to investigate the impact o

ID: 3021182 • Letter: A

Question

As part of a risk assessment study a nurse was hired to investigate the impact of a smelter on the level of lead in the blood of children living near the smelter. Ten children were chosen at random from those living near the smelter. A comparison group of 7 children was randomly selected from those living in an area relatively free from possible lead pollution. Blood samples were taken from the children, and lead levels determined. The following are the results (pg of lead per 100 ml of blood): Complete the analysis, with the data showing non-normality.

Explanation / Answer

Ho:there is no significant difference between children living near smelter and children living in unpolluted area H1:there is a significant difference between children living near smelter and children living in unpolluted area.

Total sum of squares(TSS)=[summation over i =1 to 17(Xi2)]-[total2/17]=4569-(72361/17)=312.4706.

Sum of squares within columns(CSS)=[(c12)/n1+(c22)/n2]-[total2/17]=[3385.6+1032.1428]-4256.5294=161.2135.

Error sum of squares=TSS-CSS=312.4706-161.2135=151.2571.

The table value of F(1,15) at 5% level of significance is 4.5431. So Fcal>Ftab, we reject Ho, i.e., we accept H1.

Therefore, there is a significant difference between children living near smelter and children living in unpolluted area.

Source of variation Sum of squares degress of freedom mean sum of squares F-test CSS 161.2135 1 161.2134 161.2134/10.0838=15.9874 ESS 151.2571 15 10.0838 TSS 312.4706 16