Statistics are drawn from populations, but a “population” doesn’t necessarily mean a physical count of bodies. It can be a collection of just about anything you can count, from galaxies in the sky to a count of trials in an experiment. Thus a statistic can be any quantity calculated fr...
**You may have noticed a slight difference between the regression estimated effect (14.84) and the true effect (14.83). This is because regression provides a “weird” variance-weighted causal effect (and not the correct weighted one we estimated manually). I created this fake dataset in ...
In the regression model y = ? 0 + ? 1 x 1 + ? 2 D 1 + ? 3 x 1 x D 1 + u where x 1 us a continuous variable and D_1 is a binary variable, what does ? 3 indicate? Given a regression, what does the coefficient a of product of multiple variables mean?
What are the two reasons why you can't conclude you have demonstrated a causal relationship based on correlational research? Correlation does not equal causation. That is very important when interpreting regression. Explain. Describe under what circumstances corre...
Question: What statistical method did Cattell use to identify traits? a. regression analysis b. meta-analysis c. factor analysis d. analysis of covariance The Trait Approach to Personality: Currently, one of the most famous and well...
A sampling distribution is the frequency distribution of a statistic over many random samples from a single population. Sampling distributions are at the very core of inferential statistics but poorly explained by most standard textbooks. The reasoning may take a minute to sink in but when it does...
What is the definition of a population mean? An F-statistic can have what values? Given two variables x and y, what does Corr(x, y) = 0 mean? Define the term mean. In the statistics equations, n refers to: What is the formula for degrees of freedom and when do you use this calc...
What Does a Confidence Interval Reveal? A confidence interval is a range of values, bounded above and below the statistic's mean, that likely would contain an unknown population parameter. Confidence level refers to the percentage of probability, or certainty, that the confidence interval would con...
How Does ANOVA Differ From a T-Test? ANOVA differs from t-tests in that ANOVA can compare three or more groups while t-tests are only useful for comparing two groups at one time. What Is Analysis of Covariance (ANCOVA)? Analysis of covariance combines ANOVA and regression. It can be use...
The most common method of test autocorrelation is the Durbin-Watson test. Without getting too technical, the Durbin-Watson is a statistic that detects autocorrelation from aregression analysis. The Durbin-Watson always produces a test number range from 0 to 4. Values closer to 0 indicate a great...