Data Analysis & Reporting Flashcards

A researcher finds a strong positive correlation (r = 0.85) between shoe size and reading ability in elementary school children. The best interpretation is:

Answer: A third variable (age) likely explains both

Correlation does not imply causation; age is a confounding variable that influences both shoe size and reading ability.

A teacher uses a rubric where different scorers give the same student essay very different scores. This assessment lacks:

Answer: Inter-rater reliability

Inter-rater reliability refers to the consistency of scores assigned by different evaluators; inconsistent scores indicate low inter-rater reliability.

A box-and-whisker plot shows the minimum, Q1, median, Q3, and maximum. The box itself represents:

Answer: The middle 50% of the data

The box in a box plot spans from Q1 to Q3, enclosing the interquartile range, which contains the middle 50% of values.

Which sampling method involves randomly selecting intact groups rather than individual participants?

Answer: Cluster sampling

Cluster sampling selects entire naturally occurring groups (like classrooms or schools) rather than choosing individuals one by one.

A school district tracks the number of students qualifying for free or reduced lunch over five years. Which statistic would best show the year-to-year rate of change?

Answer: Percentage change from year to year

Percentage change compares each year's value to the previous year's, directly showing the rate of change over time.

A histogram with many bars of roughly equal height across the full range of values describes which type of distribution?

Answer: Uniform distribution

A uniform distribution has approximately equal frequency across all value ranges, resulting in a flat histogram.

When a test consistently measures what it is supposed to measure, it is said to have high:

Answer: Validity

Validity refers to the degree to which a test actually measures the construct or skill it is intended to measure.