Midterm 1 Prep Flashcards
What is the p-value?
The probability of observing a test statistic as or more extreme than the one we observed, given that 𝐻o is true.
A lower p-value indicates stronger evidence against the null hypothesis.
What is the Normal Distribution?
A Gaussian distribution, most used distribution in statistics.
It is characterized by its bell shape and symmetry about the mean.
What does the Central Limit Theorem state?
Anything over 30~ is going to be normally distributed.
This theorem is fundamental in statistics as it justifies the use of normal distribution in many situations.
What is a Sampling Distribution?
The set of all possible sampling statistics we could have in our sample or the collection of all possible Xbars from the population.
It describes how a statistic (like the mean) varies from sample to sample.
Define Type I Error.
Rejecting 𝐻o when 𝐻o is true, also known as a false positive, denoted as 𝛼.
This error can lead to incorrect conclusions about the effectiveness of a treatment or intervention.
Define Type II Error.
Failing to reject 𝐻o when 𝐻o is false, also known as a false negative, denoted as β.
This error occurs when a test fails to identify a difference or effect that truly exists.
What is Alpha (𝛼)?
The significance level, critical region, and represents the probability of a Type I error.
Commonly set at 0.05 in many studies.
What is Beta (β)?
The probability of a Type II error.
It represents the likelihood of failing to detect an effect when there is one.
What does Power mean in statistical terms?
1 - β = Power, indicating the probability of correctly rejecting the null hypothesis.
Power increases as sample size increases or effect size increases.
What is a Critical Region?
The set of values for a statistic that would lead to a rejection of 𝐻o.
It defines the threshold for significance in hypothesis testing.
What is Paired Comparison (blocking)?
When two samples are NOT independent, with measurements on two units within a block.
This approach helps control for variability between the paired units.
What does Difference (δ) represent?
The difference between two treatment effects or group means.
It is often used in hypothesis testing to determine significance.
What is Bias in statistical terms?
Is it centered in the right place? Refers to skewness in data.
Low bias indicates that estimates are close to the true value.
Define Reliability.
The repeatability and consistency of a measurement.
High reliability means that repeated measurements produce similar results.
What is Validity?
The relevance of a measurement or assessment.
It reflects how well a test measures what it is intended to measure.
What is Chance Error?
The random deviation in a sample due to natural fluctuations when drawing from a population.
It is an unavoidable error in sampling.
What is Variance?
A statistical measure of how much a set of values deviates from the mean.
It indicates the spread or dispersion of a data set.
What is a Response Variable?
The outcome or variable being measured in a study, influenced or predicted by other variables.
It is often the dependent variable in an experiment.
What is an Explanatory Variable?
The variable that explains, predicts, or influences changes in the response variable.
It is often considered the independent variable in an analysis.
What is Randomization?
The process of assigning individuals or units in a study to different groups using a random method.
It ensures each unit has an equal chance of being placed in any group, reducing bias.
What is Restricted Randomization?
Methods that impose certain constraints on the randomization process to ensure balance between treatment groups in an experiment.
It can help control for confounding variables.
What does Blocking do in an experiment?
Converts unplanned, systematic variation into planned, systematic variation.
It helps to control for variables that could affect the outcome.
What is a Blocking Variable?
A variable used to create blocks in an experiment to control for variability.
Examples include age, gender, or any other relevant characteristic.
What does Replicate mean in an experimental context?
An independent run of an experimental condition to estimate variability.
Replication is crucial for validating experimental results.