math skills

Question 1

standard deviation on a calc

Answer 1

• mode: stat
• 1-VAR
• enter all table data followed by =
• AC
• shift 1
• VAR
• x = mean sx = standard deviation

Question 2

spearman’s rank test, what happens if 2 variables being ranked are the same

Answer 2

you average their positions eg if they’re in positions 8 and 9 you’d do 8+9/2 = 8.5

Question 3

spearman’s rank stats test

Answer 3

rank variable 1 from lowest to highest , then match variable 2 up to it
work out difference between the ranks and square it
add up all D^2 and then sub into equation

how closely correlated is how close the number is to +-1

compare to critical value

Question 4

degrees of freedom for a t-test

Answer 4

n = number of things

(n1 + n2) - 2