Stats Informed Decisions Using Data, Chapter 9

What is a point estimate?

is a single value used to approximate a population parameter

Formula for point estimate for a population mean

What is the equation for a point estimate for a population proportion?

what is a confidence interval?

a range of values used to estimate a population parameter, with a specified level of confidence (e.g., 95%)

how is the confidence interval denoted?

Formula for standard deviation of the distribution of the same proportion

What is the margin of error?

the range + to - from a point estimate to create a confidence interval

How is the margin of error for means calculated?

How is the margin of error for proportions calculated?

What is the critical value?

a factor that determines the margin of error in confidence intervals or hypothesis tests

What is the critical value denoted as for a z-distribution?

z*

What is the critical value denoted as for a t-distribution?

t*

What does a (1-alpha)•100% confidence interval indicate?

the range of values within which the true population parameter is expected to lie

What does alpha indicate in the (1-alpha)•100% confidence interval?

Significance level

alpha=0.05 would correlate with what percent confidence?

95%

What effect does level of confidence have on the margin of error?

As the level of confidence increases, the margin of error also increases

what effect does sample size have on the margin of error?

sample size (n) increases, the margin of error decreases

what is the formula for sample size needed for a specified margin of error (E) and level of confidence (1-alpha)?

what is the formula for sample size needed for a specified margin of error (E) and level of confidence (1-alpha) for proportions?

What does the sample size needed for a specified margin of error (E) and level of confidence (1-alpha) determine?

ensures that the margin of error is within the specified limit for the given confidence level