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a variable that takes on a numerical value for which it makes sense to do arithmetic operations like averaging
Type 2 Error
An error made by failing to reject (accepting) the null hypothesis when in fact it is false
Law of large numbers
a property that states as the number of observations increases, the mean (statistic) of the observed values gets closer and closer to the true parameter
the probability of observing a value for a test statistic as extreme or more than the hypothesized given value
the relationship between two variables when the plotting of them in a scatterplot depicts a straight-line pattern
the method of collecting, organizing, and then describing data using graphs, numerical summaries in order to make statistical inferences
the statistically unsound method of using a regression line to make predictions outside the range of values
a variable that belongs to one of many levels or groups. A proportion is formed by counting how many of the observations belong to the individual groups.
central limit theorem
as a randomly collected sample size gets large enough, the sampling distribution becomes more normal regardless of population distribution
a numerical value that measures the spread of a distribution by looking at how far the observations are from the mean
a numerical value that measures the strength and direction of the linear relationship between two quantitative variables
a variable that has a significant effect on the response variable in the relationship between two variables in a study, but is not one of the two variables being studied
this refers to a reversal of the direction of a comparison of an association when data from several groups are combined to form a single group
double blind experiment
an experiment in which neither the subjects nor the people conducting the experiment know which treatment a subject receives
the probability that a fixed level of significance will correctly reject a false null hypothesis
this occurs when some groups in the population are left out of the process of choosing a sample
a statistically unsound method of survey in which people choose themselves by responding to a general appeal
Matched Pairs Design
an experiment in which the subjects are matched in pairs and each treatment is given to one subject in each pair
the pattern of a data set. It tells us the range of the variable, the frequency of each value, the center, and the shape (normal or skewed) of the data.
Stratified Random Sample
a sample collected by dividing up the population into homogeneous groups and then using an SRS to sample from each group
a confidence interval or the outcome of a significance test that is unchanged when the assumptions are violated OR a resistant statistical procedure
this occurs when an individual chosen for a sample can't be contacted or refuses to cooperate
a numerical value that is estimated from a sample distribution that is equal to the true value of the population (statistic=parameter)
a surveying or experimental phenomenon that occurs when the individual outcomes are uncertain
the statistical hypothesis that states that there is no effect or no change in the claimed population parameter
an interval computed from sample data by a method that has a certain insurance of producing an interval containing the true population parameter
Critical Value (upper)
a numerical value, z or t that has probability = p, lying to the right of it under the standard normal curve
a specific experimental condition applied to the units in order to change the environment to detect a significant effect
Least Square Regression
the line that makes the sum of squares of the vertical distances of the data points from the lines as small as possible. Used for making predictions.
Square of the Correlation
r-squared, the fraction of variation in the values of y that is explained by the least-squares regression of y on x
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