Biological Statistics Flashcards
measurement variable
variable that is measured
nominal variable
variable that is classified by observations into categories
null hypothesis (H0)
hypothesis that states that there is no relationship or effect between variables
alternative hypothesis (H1)
hypothesis which states there is relationship or effect between variables
confounding variables
variable that influences both the dependent variable and independent variable
unable to be easily controlled
mean (X)
average
sum of all values divided by number of values in set
function of mean
determination of central tendency
median
single value in middle of sorted list from lowest value to highest value
mode
most frequent value in set of data
most useful with imprecise measurements
unimodal set
set of data with only 1 mode
bimodal set
set of data with 2 modes
range
difference between maximum and minimum of set of data
standard deviation (σ)
measure of amount of variation or dispersion of set of values in relation to mean
can be used either as measure of variation within set of data or reliability of measurement
error bars
graphical representation of variability of data
able to show range of data, range of precision of measurement, or standard deviation
t-test
statistical hypothesis test used to compare means of 2 different samples
result of t-test
p-value
p-value
P
value which indicates probability that null hypothesis is correct
significance of P ≥ 0.05
no statistical significance
indicates null hypothesis cannot be rejected
significance of P < 0.05
statistical significance
significance of P < 0.01
high statistical significance
indicates null hypothesis can be rejected
analysis of variance
ANOVA
statistical hypothesis test used to determine presence of statistically significant difference between means of 2+ samples
result of analysis of variance
F-statistic (used to find p-value)
correlation
strength and direction of relationship between values
Pearson correlation coefficient (r)
statistic that measures linear correlation between 2 variables
range of Pearson correlation coefficient
between -1 and +1
significance of r = -1
perfect negative correlation between 2 variables
significance of r = 0
no correlation between 2 variables
significance of r = +1
perfect positive correlation between 2 variables
chi-squared test
χ2 test
statistical hypothesis test used to determine presence of statistically significant difference between expected values and observed values
