Confidence Intervals
Statistic that provides an estimate of a population parameter
What is Point estimator
Takes numerical values that describe the outcomes of a random process.
What is random variable
In a statistical study, is the entire group of individuals we want information about.
What is population
Number that describes some characteristic of a sample.
What is statistic
Formal procedure for using observed data to decide between two competing claims (the null hypothesis and the alternative hypothesis). The claims are usually statements about parameters.
What is significance test
Specific value of a point estimator from a sample.
What is Point estimate
Of a random variable, gives its possible values and their probabilities.
What is probability distribution
Collects data from every individual in the population.
What is census
A number that describes some characteristic of a population.
What is parameter
Claim we weigh evidence against in a significance test. Often the null hypothesis is a statement of "no difference."
What is null hypothesis H₀
Gives an interval of plausible values for a parameter. The interval is calculated from sample data and has the form point estimate ± margin of error or, alternatively, statistic ± (critical value) * (standard error of statistic)
what is confidence interval
χ takes a fixed set of possible values with gaps between them.
What is discrete random variable
A subset of individuals in the population from which we collect data.
What is sample
The fact that different random samples of the same size from the same population produce different estimates
What is sampling variability
The claim that we are trying to find evidence for in a significance test.
What is alternative hypothesis Hₐ
Overall success rate of the method used to calculate the confidence interval. In C% of all possible samples, the method would yield an interval that captures the true parameter value when the conditions for inference are met.
What is confidence level C
Its average value over many, many trials of the same random process.
What is mean (expected value) of a discrete random variable
A study that collects data from a sample to learn about the population from which the sample was selected.
What is sample survey
The distribution of values taken by a statistic in all possible samples of the same size from the same population
What is sampling distribution
An alternative hypothesis is one-sided if it states that a parameter is greater than the null value or if it states that the parameter is less than the null value.
What is one-sided alternative hypothesis
Describes how far, at most, we expect the estimate to vary from the true population value. That is, the difference between the point estimate and the true parameter value will be less than the margin of error in C% of all samples, where C is the confidence level.
What is margin of error
Measures how much the values of the variable typically vary from the mean in many, many trials of the random process.
What is standard deviation of a discrete random variable
Selects individuals from the population who are easy to reach.
What is Convenience sampling
A statistic used for estimating a parameter is unbiased if the mean of its sampling distribution is equal to the value of the parameter being estimated.
What is unbiased estimator
The alternative hypothesis is two-sided if it states that the parameter is different from the null value (it could be either smaller or larger).
What is two-sided alternative hypothesis