Full Answer Section

Slide 3: What is descriptive statistics?

Slide 4: Presenter notes:

• Descriptive statistics are a set of tools used to summarize data and describe its main features.
• They are used to answer questions such as:
  • What is the average height of the students in this class?
  • What is the distribution of test scores in this class?
  • What are the most common eye colors in this population?

Slide 5: Reliability

Slide 6: Presenter notes:

• Reliability is the ability of a measurement to produce consistent results over time.
• A reliable measurement is one that will produce the same results if it is taken multiple times.
• There are several ways to measure reliability, such as test-retest reliability and inter-rater reliability.

Slide 7: Test-retest reliability

Slide 8: Presenter notes:

• Test-retest reliability is the ability of a measurement to produce the same results if it is taken multiple times.
• To measure test-retest reliability, a measurement is given to the same group of people on two separate occasions.
• The correlation between the two sets of scores is then calculated.

Slide 9: Inter-rater reliability

Slide 10: Presenter notes:

• Inter-rater reliability is the ability of two or more raters to produce the same results when scoring a measurement.
• To measure inter-rater reliability, two or more raters score the same set of data.
• The correlation between the two sets of scores is then calculated.

Slide 11: Validity

Slide 12: Presenter notes:

• Validity is the ability of a measurement to measure what it is supposed to measure.
• A valid measurement is one that accurately reflects the true value of the construct that it is measuring.
• There are several ways to measure validity, such as content validity, criterion validity, and construct validity.

Slide 13: Content validity

Slide 14: Presenter notes:

• Content validity is the extent to which a measurement covers the content domain that it is supposed to measure.
• To measure content validity, a panel of experts reviews the measurement to make sure that it covers all of the important aspects of the content domain.

Slide 15: Criterion validity

Slide 16: Presenter notes:

• Criterion validity is the extent to which a measurement is correlated with a criterion measure.
• A criterion measure is a measure that is known to be valid for the construct that is being measured.
• There are two types of criterion validity: concurrent validity and predictive validity.

Slide 17: Concurrent validity

Slide 18: Presenter notes:

• Concurrent validity is the extent to which a measurement is correlated with a criterion measure that is administered at the same time.
• To measure concurrent validity, the measurement is correlated with the criterion measure in a sample of people.

Slide 19: Predictive validity

Slide 20: Presenter notes:

• Predictive validity is the extent to which a measurement is correlated with a criterion measure that is administered at a later time.
• To measure predictive validity, the measurement is correlated with the criterion measure in a sample of people, and then the measurement is used to predict the scores on the criterion measure.

Slide 21: Bell curve

Slide 22: Presenter notes:

• A bell curve is a symmetrical distribution of data points that resembles a bell.
• The bell curve is also known as the normal distribution.
• The bell curve is often used to represent the distribution of test scores or other types of data.

Slide 23: The normal distribution

Slide 24: Presenter notes