module 6 + article review for stats

when do you use a histogram vs scatterplot?

histogram (one quantitative variables) → show distribution, skew, normality

scatterplot (two quantitative variables) → shows correlation, regression

how do you increase power?

larger sample size, larger effect size, lower variability, within-subjects designs

when do you use an independent t-test vs paired t-test

independent- comparing two different groups (ex- men vs women)

paired- same people measured twice (ex- before vs after training)

when is a mixed ANOVA used?

when one between-subjects factor and one within-subjects factor is present

example → when there is a control vs exercise group (between-subjects) that is measured before and after training (within-subjects)

which type of ANOVA is used in the astorino article ?

two way repeated measures ANOVA:

• researchers compare an experimental and control group (between subjects) while measuring participants before and after training (within subjects)

correlation vs regression

correlation- are the variables related?

regression- can one variable PREDICT another?

• example- predicting VO2max from hours of training

parametric tests

require assumptions like approximate normality and homogeneity of variance

include independent t-test, paired t-test, ANOVA, pearson correlation

nonparametric tests

used when parametric assumptions are not met

include Mann-Whitney U, Wilcoxon signed rank, Kruskal-Wallis, Spearman correlation

which test do you use when comparing two groups?

independent t-test (or paired t-test if its the same people)

what test do you use when comparing three or more groups?

one way anova

what test do you use when looking at whether two variables are related?

pearson correlation

what assumptions need to be met to use parametric tests?

approximate normality and homogeneity of variance

if assumptions aren’t met for independent t-test, what test do you use?

mann-whitney U

if assumptions aren’t met for paired t-test, what test do you use?

wilcoxon signed rank

if assumptions aren’t met for one-way anova, what test do you use?

kruskal-wallis

if assumptions aren’t met for pearason correlation, what test do you use?

spearman correlation

what is the purpose of the article?

determine whether 2-3 weeks of HIIT improves VO2 max, BP, HR, muscular force, and power output in recreationally active young adults

who are the participants in the article?

20 in HIIT group, 9 in controls

all young, recreational active men and women

what is the independent variable of the study?

HIIT training (control vs HIIT group)

what ar ethe dependent variables of the study?

VO2 m ax, BP, HR, power output, and muscular force

what did the researchers hypothesize?

researchers predicted that VO2max would increase, strength would increase, BP and HR would not change, and change in VO2max would relate to baseline VO2max

what are the statistics used in the study?

independent t-test, two way repeated measure ANOVA, tykey post hox test, correlation, multiple regression

what are the main findings of the study?

HIIT significantly increased VO2max, O2 pulse, and peak power

no significant change in BP, HR, or muscular force

what are the correlations of the study?

greater improvement in VO2max was associated with: lower baseline VO2max (neg correlation) and higher fatigue index (positive correlation)