# Harley (2003) examined effects on growth of the red algae Ma

Harley (2003) examined effects on growth of the red algae Mazzaella parksii, which forms lawn-likegrowths in the intertidal region. He focused on two factors: (1) location and(2) herbivore abundance. The two locations were in areas along the shoreline belowwhere this algae normally occurs (Low zone) and in areas along the shorelinewhere this algae does normally grows (Mid zone). For herbivore abundance, hehad areas where limpets (Lottiaspecies) were removed (Absent) and areas where limpets were not removed(Present). Harley then measured the area covered by Mazzaella (in cm2) for each replicate plot, and obtainedthe following data (NOTE: 0.5 has been added to each value to remove any zeroesfrom the data):HeightHerbivoresAreaHeightHerbivoresArealowabsent88.46midabsent0.50lowabsent1188.02midabsent622.54lowabsent2178.41midabsent2168.20lowabsent276.96midabsent0.50lowabsent594.26midabsent26.42lowabsent1470.77midabsent38.20lowabsent1140.90midabsent2204.33lowabsent3732.72midabsent524.36lowabsent1257.14midabsent377.49lowabsent2132.08midabsent1378.88lowabsent1254.00midabsent201.56lowabsent627.25midabsent9.92lowabsent0.50midabsent467.03 lowabsent1689.11midabsent276.96lowabsent1307.41midabsent2073.96lowabsent1746.44midabsent2297.80lowpresent143.44midpresent0.50lowpresent209.42midpresent1037.23lowpresent0.50midpresent1230.44lowpresent64.12midpresent307.59lowpresent0.50midpresent38.98lowpresent0.50midpresent170.15lowpresent763.91midpresent657.09lowpresent1847.76midpresent1332.54lowpresent9.92midpresent1407.94lowpresent69.62midpresent2095.95lowpresent0.50midpresent401.05lowpresent16.99midpresent99.46lowpresent0.50midpresent7.57lowpresent1294.05midpresent1610.57lowpresent12.28midpresent1665.55lowpresent7.57midpresent 2012.69A) Use a two-factor ANOVA to analyze these data andinterpret your results. The data are not currently set up correctly for doing atwo-factor ANOVA in Excel, so you will likely need to rearrange them!B) Test these data to see if (1) they are normallydistributed and (2) the groups have equal variances.C) If either assumption is violated, perform a datatransformation to best eliminate the problem (you may or may not be able to completelyeliminate any violations!). Then perform a second two-factor ANOVA, this timeusing the transformed data. How do your F-values and P-values differ if youcompare the results of the two ANOVAs?