Terms Flashcards
Hø
The null hypothesis
Ha
The alternate hypothesis
What is a z test and how can you determine when to use one?
A z test is used for large samples. When the sample size is greater than 30, a z test can be used.
σ
What does the symbol represent?
Standard deviation
n
What does the symbol represent?
Sample size
Type II Error
Failure to reject when null hypothesis is not true.
Type I Error
When a null hypothesis
is wrongly rejected.
When should you use a Type II error?
We use a Type II error when the null hypothesis is false.
What is a right tailed test ?
When your hypothesis statement contains a greater than symbol. In word problems, words like “increased” help determine if it’s a right tailed test.
a
What does the symbol represent?
significance level
confidence level
The percent of confidence
intervals that contain the true
population parameter when
repeated samples are taken
critical value
A measure of how many standard errors above or below the center of the confidence interval to go to achieve the desired level of
confidence
degrees of freedom
A measure related to the sample size (n) derived from the calculation of the sample standard deviation. Formula for a t-distribution: n-1
margin of error
A quantity that can be added or subtracted from a point estimate to construct a confidence interval.
margin of error
A quantity that can be added or subtracted from a point estimate to construct a confidence interval.
Formula: Critical Value x Standard
Error
Two tailed test
Where the critical area of a distribution is two sided and test if a sample is greater or less than a range of values. In a word problem, worlds like “differed” tell us it’ll be a two tailed test.
What is a t test and how can you determine when to use one?
A t test is used when standard deviation is unknown and there are two or fewer groups. We can determine when to use one when we are given sample standard deviation and the sample size is less than 30 or small.
