Confidence Intervals Flashcards
Success rate method
The proportion of times repeated applications of this method would capture the true population
General formula for confidence intervals
Estimate + and - margin of error
Standard error
Term used when the standard deviation is found with the equation:
s~ _p
Conditions for confidence intervals
- SRS
- np>10 and n(1-p)>10
- n< .1population
The standard deviation of the set do differences of the sample proportions is approximately equal to…
__p1(1-p1)__ + __p2(1-p2)__
✔️ n1 n2
Generally when we want a smaller, more precise interval estimate, we….
Decrease the degree of confidence or
Increase the sample size
Standard deviation of the residuals
se= __Σ(y-y
Standard error of the slope
SE(b1)= __se__
sx(✔️n-1)
Increasing the standard error of the residuals/line increases the standard error or the slope
sx= range of x values= Σ(xi-x)^2
Result of a smaller margin of error
A smaller confidence level
If p
It is unlikely that the given sample proportion result would be obtained unless the true percentage was between .77 and .87
There is 95% confidence level that the maternal ancestor to humans lives 273,000 and 177,000 years ago. What is meant by “95% confidence level” in this context?
95% of all random samples of data obtained by this method will yield intervals that capture the true age
The margin of error in a confidence interval estimate using z-scores covers…
Sampling variability
Under what conditions would it be meaningful to construct a confidence interval estimate when the data consists of the entire population?
Never
