Statistics, Significance Testing And Different Types Of Tests Flashcards
What are descriptive statistics? And give three examples
Statistics in which frequency distribution or relations between variables are described
Examples: mean, median & mode
What are inferential statistics? And what is the other name for inferential statistics?
Also known as inductive statistics, is the body of knowledge that deals with tests of significance
What are tests of statistical significance
Techniques that help us to generalize a larger group
A class of statistical computations that indicate the likelihood that the relationship observed between variables in a sample can be attributed to sampling error only
What are the three levels of significance?
0.5,0.1 and 0.001 ( 5/100, 1/100, 1/1000)
What is the null hypothesis?
A statement claiming that two variables in the population are unrelated
What is the alternative hypothesis?
A statement claiming that two variables are related
What is the fallacy of affirming the consequent?
A principle of logic that suggests that the only way to “prove” or validate the alternative or research hypothesis is to demonstrate that the null is untrue
What are the steps in significance testing?
- Null and alternative hypothesis
- Test statistic
- p-value
- Decision
Explain what happens in the null and alternative step
Convert the research question into null and alternative hypotheses
Explain what happens in the test statistic step and State the formula
Calculating the Z statistic from the data (a= x-xbar /s)
Explain what happens in the P value step
The test statistic is converted into a conditional probability called the p-value
Define the p-value
A measure of the probability that a difference between groups during research happened by chance which is calculated from observed data
What happens in the decision step
If p< alpha the null is rejected ; otherwise accept the null hypothesis for lack of supporting evidence
Differentiate between a directional and non-directional hypothesis
A directional hypothesis specifies the direction of the effect of the independent variable on the dependent variable
A non-directional hypothesis does not specify the direction of the effect of the independent variable on the dependent variable
What do positive and negative z-scores mean?
A positive z-score means that the original score was above the mean
A negative z-score means that the original score was below the mean
What is a one sample z-test?
A test of significance that can be performed when we know the population’s standard deviation as well as its mean
What is a one sample t-test?
A test that can be performed when we know the population’s mean but not its standard deviation
What is a one sample test?
Tests that can compare data from a sample of similar data in a population
What is a t-test?
A test of significance similar to the z-test but used when the population’s standard deviation is unknown
When should a t-test for a single sample be used?
When the mean of a sample is compared to the mean of the population
When should a two sample t-test be used?
When you have two groups or two sets of data and you wish to compare the mean scores
Differentiate between type 1 and type 2 errors
Type 1: probability of falsely rejecting a true null hypothesis when it is true - false positive
type 2: the incorrect retaining of a false null hypothesis - false negative
Why is it important to avoid type 1 errors?
Because it we do not, the research will be flawed and can have potentially fatal mistakes
