L8 Flashcards
What is the difference between an estimator and an estimate
The estimator is the statistic while the the estimate is a particular instance of the estimate
What is the margin of error community made up of
The standard error times the confidence level
What foes it mean that an interval is a 95% confidence interval for my
That we know that 95% of times the population mean will fall within the point estimator +- the margin of error
Is the population mean a variable
No
What is the relationship between the confidence level and confidence coefficient
The confidence level is the confidence coefficient in percent
What is the relationship between the confidence coefficient and the significance level
The confidence coefficient is 1-significance level
How do you get a confidence interval that corresponds to a particular confidence level
You use the z value that returns the corresponding significance level divided by 2 as a multiplier to the standard deviation when calculating the margin of error
How do you calculate z(x) if confidence is 95%
95% confidence level is .05 significance which means that z(x) is z(.025). Than all I need to do is to see which z score returns .025 and if it is negative make it positive and reverse
What is the width of the confidence interval
Two times the margin of error
How do you increase the width of a confidence interval
Increase the variance, decrease the sample size or increase the confidence level
What is the difference between precision and confidence
Higher precision involves improving the sample while confidence can be chosen based on the significance level
The probability that the population mean can be found in the interval is not 1 or 0
False
Do we often know the population mean in the real world
No
Do we use the z distribution when the population mean is unknown
No we use the T distribution
What happens to the t distributions tail when the sample size is small
The tail becomes wider as the degree of freedom is low
