An important issue in conservation biology is how dispersal among population inf

Question

An important issue in conservation biology is how dispersal among population influences the persistence of species in a fragmented landscape. Researchers measured this in the annual plant Cardamine pensylvanica, a weed that produces explosively dispersed seeds. Four treatments were used to manipulate seed dispersal by changing the distance among experimental plant populations. These treatments were continuous (adjacent), medium, long, or separated by partitions that blocked all seed dispersal among populations (isolated.) Treatments were randomly assigned to plant populations. The data below are the number of generations that the populations persisted in 20 replicates of each treatment. The response variable here is generations persisted. You'll be conducting an anova a) How many (levels or groups) does the explanatory variable have? [1] b) Look at the plots below. Why do we have 4 boxplots and 4 QQ plots? (Hint: Recall the assumptions necessary to conduct anova.) [0.5] Generations Persisted, Continuous Group Cenerations Persisted, Medium Greup Cenerationa Persisted Long Group Generationa Persisted, Isolated Group ong c) Based on the information given, are the assumptions to conduct anova are met? [1] d) Write the null and alternative hypotheses. [0.5] e) Fill in the anova table below. For p-value indicated p-val s 0.05 or p-val> 0.05. Note, you do not need to have the exact degrees of freedom in the F Table to conclude whether p-val 3 0.05 or p-val Df MS P-Values Treatment Error Total 76 79 220 400 620 5.26

Explanation / Answer

a) There are 4 levels of the explanatory variable : continuous, isolated, medium and long.

b) There are 4 box plots for 4 levels of the explanatory variable to get summary or check for outliers for each level and 4 QQ plots for 4 levels of the explanatory variable to check normality for each level.

c) More or less, the assumptions for normality and homoschedasticity (equal spread of each of the box plot )are met in each level.

d) Null hypothesis -> H0 : means of no. of generations persisted under all treatments are equal.
Alternative hypothesis -> H1 : not H0

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