Statistical tests

• what does the x with the bar over it represent?

  mean
• what does s squared mean

  variance (standard deviation squared)
• how do you find degrees of freedom in the unpaired t-test


  $(n1-1)+$$(n2-1)$
• what does it mean if p>critical value

  there is a less than 5% probability that any difference observed is due to chance. So we reject the null hypothesis as there is a statistically significant difference between the means
• what do the symbols mean in the spearman's rank equations?

  $r=$$1- (6√∑di^2/n^3-n)$


  di= difference between the two ranks of the individual

  n= the number of individuals in the sample
• how do you find the degrees of freedom in the spearman's rank test

  it is the number of individuals
• what do the symbols in Simpsons index of diversity equation mean

  $D=$$1- (∑(n/N)^2)$


  n= number of organisms in one species

  N= total number of all organisms
• what does a Simpsons index close to 1 mean

  habitat is more diverse
• what is the equation for proportion of polymorphic gene loci

  number of polymorphic gene loci/total number of loci
• what is a polymorphic gene

  gene with more than 1 allele