PROTEUS

              

 

 

 

 

 

 

 

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# 78      NEW ANOVA CHALLENGE: (complete problem and solution) Does indoor air quality depend on external air quality or open windows, or both?
DATA TABLE
GOOD MODERATE POOR
CLO OPN CLO OPN CLO OPN
N=10 N=10 N=10 N=10 N=10 N=10
MEAN=49.6 MEAN=36.3 MEAN=49.4 MEAN=45.6 MEAN=49.7 MEAN=54.5
ANOVA TABLE
source SS df MS F P
all groups 1842.53        
EAQ 810.13        
wind O/C 240.00        
interaction          
residual          
total 2570.73        

INTERPRETATION (Q # 71):

 

Ho3: "No interaction between EAQ and IAQ in terms of whether windows were opened".

F(interaction): 29.38 2,54 df. P<0.01 Reject Ho

The interaction analysis shows that the o/c state of windows interacts strongly with the EAQ in terms of IAQ. The emphasis in the interpretation will therefore be on the effects of one independent variable within each level of the other independent variable.

 

Ho1: "regardless of the open/closed state of the windows, external air quality has no effect on indoor air quality"
Overall, EAQ had a strong effect upon IAQ: The IAQ was best (43.1p/10cc) when the EAQ was "good", and worst (52.1p/10cc) when EAQ was "poor". This effect is statistically significant at 0.01.

   F(external Q): 30.04, 2,54 df, P<0.01 Reject Ho

In buildings with open windows, this effect is found to be even stronger (36.6 p/10cc in "good" EAQ), to 54.5 p/10cc in "poor" EAQ). In buildings with closed windows there is no noticeable effect, with IAQ being maintained between 49.4 to 49.7 p/10cc throughout.

 

Ho2:  "Regardless of the EAQ, the open/closed state of the windows has no effect on IAQ."
Overall, closed buildings showed a higher (poorer) particle count than open buildings (49.6 v 45.6 p/10cc), This was statistically significant at 0,01.

   F(windows): 17.78, 1,54 df. P<0,01 Reject Ho

When this effect is considered separately within each type of EAQ, the effect is clear. In "g" EAQ, open bldgs have much better IAQ than closed bldgs (36.6 v 49.6 p/10cc); in "m" conditions, the IAQ is similar (45.6 v 49.4 p/10cc), whereas in "p" conditions, open windows appears to produce much worse IAQ than in closed bldgs (54.5 v 49.7 p/10cc)