biology stats📊📈

Question 1

when to use chi squared test

Answer 1

• when looking at frequencies( different categories)

- when seeing whether observations differ from expected results

Question 2

when to use spearmans rank

Answer 2

-when looking at relationship between two variables

Question 3

when to use students t test/ unpaired t test

Answer 3

-to see whether there is a difference in means in two independent groups

Question 4

when to use paired t test

Answer 4

-to see if there is difference in mean between same group before and after a change

Question 5

what does 5% significance mean

Answer 5

less than 5% of results due to chance

Question 6

how to find degrees of freedom for unpaired t test

Answer 6

(n1 + n2 - 2)

so sample size of each group take away 2 because there are two groups

Question 7

how to find degrees of freedom for chi squared

Answer 7

number of categories take away 1

Question 8

hoe to find degrees of freedom for spearmans rank

Answer 8

number of pairs of data (number of plots)

Question 9

when is t test result significant

Answer 9

t > critical value

reject null hypothesis

significant difference between groups with less than 5% results due to chance

Question 10

when is chi squared result significant

Answer 10

x > critical value

reject null hypothesis

significant difference between expected and observed with less than 5% results due to chance

Question 11

when is spearman’s rank result significant

Answer 11

closer to 1 or -1 means stronger correlation, 0 means no correlation

rs > critical value

reject null hypothesis

significant correlation with less than 5% results due to chance