Stats

Question 1

What is variance

Answer 1

STD^2

Question 2

how to find STD

Answer 2

Question 3

What is Q-test

Answer 3

• way to reject outliers

Q= gap/range

-gap= outlier-closest #

look at Q chart, if Qcalc > Qcritical REJECT value

Question 4

What is grubbs test

Answer 4

G = | outlier -average | / STD

• if Gcalc > G critical REJECT

Question 5

What is a confidence interval

Answer 5

u = av +/- (ts )/ √n

• u= true value

if T calc > T table results are significantly different

Question 6

What is T test 1

Answer 6

• comparing measured value with known value

Tcalc= ( |u| - ave)/s · √n

Question 7

What is T test 2

Answer 7

• comparing replicate measuremnts: diff experiments, diff seasons, sites or people

1. Ftest: Fcalc = S1^2/S2^2 (S1 > S2)
2. Look at F table:

A) if F calc < F table:

• find s pooled formula (given on mid)
• tcalc= |Ave 1- Ave 2|/ S pooled • (√(n1 n2)/n1 + n2)
• dof = n1 +n2 -2

B) if F calc > F table

• use t calc and dof formula given on midterm

Question 8

What is T test 3

Answer 8

compare individual differences

• paired sinlge measurements (same analysis different methods or several samples)
• 2 methods to make single measurement on multiple samples

Tcalc = ( |d|/Sd ) • √n