Chapter 7 Flashcards
When do you use a z test?
When the population parameters are known
How are z tests and t tests similar?
Both are a probability distribution
What does the sampling distribution look like for a t test?
Symmetrical
True or false: t tests are affect by sample size?
True
What does a one sample t test do?
Compare a single sample mean with the population mean
What does a two sample t test do?
Compare two sample to one another
What are the two types of two sample t tests?
Independent/between and repeated/within
Example of independent measures?
People with and without pets, measure their stress level
Example of independent measures?
Collecting data before and after people try a weight loss diet
How do you find the population means with independent samples?
estimate by taking two samples
What distribution is created for an independent sample
A sample distribution of mean differences
What are other names for repeated measures t tests?
Paired t test, within subjects, matched, or dependent samples
What does a repeated measures t test do?
Measures the same sample over time
What does independent measures require?
Homogeneity of variance
What is the df for independent measures?
df = n1 + n2 -2
What is the df for repeated measures?
df = n-1
When are findings significant?
When the null hypothesis is rejected?
What does statistical significance say?
Whether the observed effect is likely to be due to chance only
What does statistical significance not tell us?
The magnitude of the effect
What is a criticism of hypothesis testing?
Results are sample size dependent
What is effect size?
The magnitude or size of an effect
What is raw metric?
Reports the effect size as the difference between the means
Standardized mean differences
Uses Cohen’s d and represents the SD unit differences between groups
What is percentage explained?
Uses R^2 and represents the proportion of variance that can be explained by the IV
What does Cohen’s d do?
it was developed to encourage the reporting of effect size over p values
How do you calculate sample mean from effect size?
xt = u + (dxo)
What type of process is hypothesis testing?
Inferential
What error is Type I?
when you reject the null but it is actually true
What error is Type II?
Failing to reject the null when you can
