Statistical Inference Flashcards
Define Inferential Statistics
Estimating big population results based on sample results
What is a Confidence Interval ( CI)?
Estimation of population mean (μ)
The formula of Confidence Interval is:
μ = X - Z(SEM ) Translate the equation
population mean = mean - Z score “level of confidence”
Standard Error
How do you know you have the correct answer for Confidence Interal (I)?
Answer is (2) values because it identifies the mean is between an interval
What is Standard Error of the Mean (SEM)?
Amount of Error in the sample mean, used a predictor for the population area
The formula for Standard Error of the Mean (SEM) is :
SEM = SD / SQRT “N” Translate the queation
Standard Error of the Mean = ___Standard Deviation___
Squareroot of “N”
In the formula of Standard Error of the Mean, What is the inverse relation when Standard Deviation is large?
When Standard Deviation is large, Standard Area is Large, and total number is small.
When Number is large and Standard Deviation is less, Standard Error of the mean is small
What is the Level of Confidence?
Probability that a statement is correct
Is higher level of confidence better? Yes and No, why?
Larger Confidence and the mean will more likely to fall in the confidence Interval
Larger Confidence also gives makes you less certain of an exact value
What is the most common confidence interval?
95% with a Z-Score of 1.96
How would you find the Z-score for any Confidence Interval?
Example of a 90% CI
- ) Divide 90% by 2
- ) Find that calculated %’s Z-score on the Z-Table
- )Use Z-Score and plug into the CI formula
- ) Solve for Z? *Listen to Recording
When given a Z-score, how do you find the % confidence interval?
Multiply corresponding % of Z-score by 2
***Example of finding Confidence Interval when given (N), SD and Xbar - The High and Low Interval
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