Variables, Correlation and Statistics

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

In an experiment examining the impact of sleep duration on test performance, what represents the independent variable (IV)?

  • The duration of sleep the night before the test. (correct)
  • The students' anxiety levels.
  • The score achieved on the test.
  • The difficulty of the test questions.

A negative correlation between exercise and weight indicates that as exercise increases, weight tends to increase as well.

False (B)

What does a high standard deviation indicate about a dataset?

Greater variability

A researcher rejects the null hypothesis when it is actually true. This is an example of a Type ______ error.

<p>I</p> Signup and view all the answers

Match the following terms with their definitions:

<p>Mean = The average of a set of numbers. Median = The middle value in an ordered set of numbers. Mode = The value that appears most frequently in a set of numbers. Standard Deviation = A measure of the dispersion of a set of values.</p> Signup and view all the answers

If a depression scale consistently produces similar results over multiple administrations but does not accurately capture the construct of depression, it is said to have:

<p>High reliability but low validity. (B)</p> Signup and view all the answers

Cohen's d measures statistical significance, indicating whether an effect is likely due to chance.

<p>False (B)</p> Signup and view all the answers

What is the primary purpose of using a Z-score?

<p>Standardize scores</p> Signup and view all the answers

The ______ hypothesis states that there is no effect or difference between the groups being studied.

<p>null</p> Signup and view all the answers

In hypothesis testing, what does a larger sample size generally lead to?

<p>Increased statistical power. (D)</p> Signup and view all the answers

Flashcards

Independent Variable (IV)

The variable you manipulate in an experiment.

Dependent Variable (DV)

The outcome you measure in an experiment.

Categorical Variables

Variables with distinct categories.

Continuous Variables

Variables that can take any value within a range.

Signup and view all the flashcards

Mean

The average score.

Signup and view all the flashcards

Median

The middle score when data is ordered.

Signup and view all the flashcards

Mode

The most frequent score.

Signup and view all the flashcards

Standard Deviation

How spread out the data is around the mean.

Signup and view all the flashcards

Correlation

Shows how two variables are related.

Signup and view all the flashcards

Null Hypothesis (H0)

There’s no effect or difference.

Signup and view all the flashcards

Study Notes

  • Study notes below

Variables

  • An independent variable (IV) is manipulated in an experiment
  • A dependent variable (DV) is the outcome that is measured
  • Categorical variables have categories
  • Continuous variables can take any value within a range

Central Tendency & Variability

  • Mean is the average score
  • Median is the middle score when data is ordered
  • Mode is the most frequent score
  • Standard deviation indicates how spread out the data is around the mean
  • Variance is the square of the standard deviation

Correlation & Covariance

  • Correlation shows how two variables are related
  • Positive correlation: As one variable goes up, so does the other
  • Negative correlation: As one variable goes up, the other goes down
  • Covariance is a measure of how two variables vary together

Reliability & Validity

  • Validity measures how well an experiment measures what it claims to
  • Content, construct, and criterion are types of validity
  • Reliability measures the consistency of the measurement

Hypothesis Testing

  • Null hypothesis (H0): There’s no effect or difference
  • Alternative hypothesis (H1): There is an effect or difference
  • Type I error involves a false positive, rejecting a true null hypothesis
  • Type II error involves a false negative, failing to reject a false null hypothesis
  • Larger sample sizes increase statistical power, so it's easier to detect a true effect

Z-scores & Z-tests

  • Z-score indicates how many standard deviations a score is from the mean
  • Z-test is used when the population variance is known, to compare a sample mean to a population mean

Statistical Significance & Effect Sizes

  • Statistical significance indicates whether an effect is likely due to chance (p-value)
  • Effect Size (Cohen’s d) measures the size of the effect, independent of sample size
    • Small effect = 0.2
    • Medium = 0.5
    • Large = 0.8
  • Confidence intervals show the range of values that are likely to contain the population parameter

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Quiz Team

More Like This

Use Quizgecko on...
Browser
Browser