non-parametric alternative: Paired T-test
Wilcoxon signed-rank test
non-parametric alternative: Two sample T-Test
Mann-Whitney U test
non-parametric alternative: One-way ANOVA
Kruskal-Wallis test
non-parametric alternative: Repeated-measures ANOVA
Friedman test
non-parametric alternative: Correlation
Spearman’s rank correlation
non-parametric alternative: Chi-square test for independence
Fisher’s exact test
non-parametric alternative: Simple linear regression
rank-based regression
Chi-square contingency analysis test steps and when to use:
When you have two or more independent samples with categorical outcomes. (Snakes with or without bands from two different areas).
Write out contingency table
Calculate expected counts - (Row total * column total)/Grand total
With expected value, calculate chi square.
Df = rows - 1 * columns - 1
Chi-square = n(ad-bc)^2/(a+b)(c+d)(b+d)(a+c)
Chi-square Goodness of fit steps and when to use:
Test if observed frequencies match a theoretical model - 3:1 mendelian ratio.
Find expected counts
compute chi-square
df= categories -1
One sample t-test steps and when to use:
Comparing a sample mean to a known constant
(observed body temp to expected body temp)
find standard deviation and mean.
Calculate t
How to compare means with unequal variance
Welch’s T-test
Paired t-test steps and when to use:
Compare mean of differences between a pair to null hypothesis value.
(cooling constant of mice, reheated vs fresh)
Find standard deviation and mean of difference between pairs.
calculate T
2 sample T-test steps and when to use:
Comparing means of two independent groups.
Need to find s^2 for both groups
pooled variance
SE
Then calculate T using means and SE
Assumptions: Normality in both groups and equal variances
Single factor ANOVA steps and when to use:
Comparing means among >2 groups.
Assumes normality and equal variances.
Compute grand mean: sum of all data/N
Compute MS Error and MS group to find F
df Error = N - k
dfGroup = k-1
Correlation
Test strength & direction of linear relationship between 2 numeric variables.
Find r and SEr
t=r/SEr
df=n-2
regression
Predicting y from x
Linear assumes the relationship can be described by a line.
Logistical is for categorical variables.
find b
find intercept (alpha)
from that get equation for y
Find SEb
t=b/SEb
Test to determine if normally distributed
Shapiro-Wilkins test
M
Chi-square goodness-of-fit assumptions
Independent observatuions
If expected counts are small, use an exact test.
Each observation falls into only one category
Chi-square contingency asumptions
Data are counts/frequencies
Independent observations
No cell should have 0 expected count
Small counts -> fisher
One-sample t-test assumptions
Response variable is numerical and continuous
dample is independent and random
Variable is normally distributed in the population
Two-sample t-test assumptions
Response variable is numerical and continuous
Samples are independent
Both groups normally distributed
Variances are equal, if not - Welch’s t-test
Paired T-test assumptions
random sample of pairs, the differences are normally distributed
ANOVA assumptions
All samples are random samples from populations that are normally distributed with equal variance.