Lecture on Z Tests to T Tests

These flashcards cover key concepts from the lecture on Z Tests to T Tests, focusing on populations, samples, hypothesis testing, and the differences between z-tests and t-tests.

What is the difference between a Population and a Sample in research?

A Population is the large group a study aims to apply to, while a Sample is the smaller group that actually participates in the study.

What analogy is used to explain the concept of Populations and Samples?

The analogy of a giant pot of soup (population) and a spoonful of that soup (sample) is used to illustrate the difference.

Why do we need two different mathematical toolkits for populations and samples?

Samples give imperfect estimates of populations, so we need one toolkit for theoretical population data and another for practical sample data.

What are the two types of hypotheses related to comparing Steve's score to his therapy group's average?

Null Hypothesis (H0): Steve's score is not meaningfully different from his group's average; Alternative Hypothesis (H1): Steve's score is meaningfully different from his group's average.

What is the alpha level convention in psychology?

The alpha level (α) is set at .05, meaning if a result is so rare that it would only happen by chance 5% of the time or less, it is considered significant.

What do the critical values for two-tailed tests indicate?

Critical values for two-tailed tests indicate where to look for rare outcomes, split equally between both tails of the distribution.

What formula is used for comparing an Individual to a Population in research?

The formula involves the individual score (X), the population mean (μ), and the population standard deviation (σ).

When using a t-test, what do you substitute for the population standard deviation?

You substitute the sample standard deviation (s) as an estimate for the unknown population standard deviation (σ).

How does the t-distribution differ from the z-distribution?

The t-distribution accounts for sample size, changing shape based on degrees of freedom, whereas the z-distribution does not.

What is the conclusion format for reporting results from a t-test?

Report includes the statistical evidence, sample mean, population mean, t-value, degrees of freedom, and significance level.