Student's T distribution Flashcards
inferences are made on what assumption?
population standard deviation was known
what test is used when SD is not known
student’s T distribution
what is the parameter measured in
degrees of feedom
how do we calculate degrees of freedom
n-1
How do inferences differ for normal distribution?
inferences are the same as described for normal but these have critical values which depend on sample size
if the sample variances are not comparable
- investigate the relationship between the means and variance
- Welch’s modified t test
- non-parametric test to compare means
- do not proceed with the test of means
proportions
make inferences about binomial data using normal inference theory
normal approximation is used for..
- estimate the number of successes in a set of trials
- estimate the population proportion of successes
- test hypotheses about the population proportion of successes
regression analysis
provides information about the nature of the relationship (e.g. linear, curvilinear) and enables predictions to be made
linear relationships with two continuous variables would use..
correlation
relationships between categorical variables are examined by..
chi squared
logistic regression is used when..
one variable is categorical
correlation
when one set of data changes proportionally with another
correlation coeficient
- strength of linear relationships
- (-1 to +1)
- sign indicates direction of the relationship
- magnitude indicates strength
- stronger the association, closer the value is to 1
pearson’s product
a measure of the strength of a linear association between two variables and is denoted by r
