Chapter 5 and 6 Flashcards
Indirect proof
taking the opposite of what you want to prove and assuming it is true
What is indirect proof used for?
In hypothesis testing, it is used to prove the null is false
What type of sample does a null hypothesis distribution take?
Random
What type of distribution does a random sample (and null hypothesis distribution) have?
It will have a normal distribution that is shaped like a bell curve
How to you find the odds of the null hypothesis being true?
Finding where the results fall on the null hypothesis distribution. This is done by converting the results to a z score
Formula for z score?
z=x-u/ox
What is x?
experimental result
What is u?
population mean
What is Ox?
The SD of the sampling distribution
What is alpha?
The amount of risk the experimenter is taking and is set before the experiment starts
What does it mean if the null hypothesis is rejected?
there is a significant difference because of the experiment’s manipulation
What does it mean if the null is failed to reject?
it means that the p value is greater than what the alpha is set at, and that there is not statistical significance
What is a Type I error?
when the null hypothesis is true but still rejected
What is a Type II error?
when the null hypothesis is accepted when it is actually false
What does a two tailed test do?
increases generalizability of test and also allows for testing of stat significance in both directions
What is the difference in the p value between a one and two tailed test?
The p value needs to be doubled in two tailed tests
Name the steps for testing the null hypothesis?
- state hypothesis
- select sig level and stat test
- Select sample and collect data
- Find region of rejection
- Calculate test stat
- Make decision
Can you ever accept the Ho or Ha?
No, you can either reject the null or fail to reject
When do you use a z test?
When the parameters (mean and SD) are known
When do you use a t test?
when the population parameters are unknown
how are degrees of freedom calculated?
N-1
What is degrees of freedom?
Our best estimate of what the population SD is
What test do you use df with?
T tests
What comes with each possible number of df’s?
a different sampling distribution
