CSET Data Analysis & Reporting 5 — Questions and Answers
Question 1: A district administrator notices that the mean SAT score increased from 1050 to 1080 after implementing a new curriculum. To determine if this change is statistically significant, the administrator should:
- Simply report the 30-point increase as significant
- Conduct a hypothesis test with appropriate controls (Correct answer)
- Assume significance because the mean increased
- Calculate only the standard deviation
Correct answer: Conduct a hypothesis test with appropriate controls
Statistical significance must be determined through formal hypothesis testing, not by observing the direction of change alone.
Question 2: In data reporting, a misleading graph often occurs when the y-axis does not start at zero. This technique can make small differences appear:
- Smaller than they actually are
- More dramatic than they actually are (Correct answer)
- More accurate
- Statistically significant
Correct answer: More dramatic than they actually are
Truncating the y-axis magnifies visual differences, making small changes look much larger than they are in absolute terms.
Question 3: A teacher wants to identify students whose scores fall more than two standard deviations below the class mean. In a normal distribution, approximately what percentage of students would this include?
- 5%
- 2.5% (Correct answer)
- 16%
- 32%
Correct answer: 2.5%
In a normal distribution, about 2.5% of values fall more than two standard deviations below the mean (the lower tail only).
Question 4: Which type of validity evidence is gathered by examining whether a test's content adequately represents the domain being assessed?
- Predictive validity
- Concurrent validity
- Content validity (Correct answer)
- Construct validity
Correct answer: Content validity
Content validity is established by evaluating whether the test items comprehensively and representatively sample the intended knowledge or skill domain.
Question 5: A researcher uses data from all students in a school rather than a sample. This approach is called:
- Stratified sampling
- A census (Correct answer)
- Convenience sampling
- Random sampling
Correct answer: A census
A census collects data from every member of the population rather than a subset, eliminating sampling error.
Question 6: Two variables have a correlation of r = -0.92. This means that as one variable increases, the other tends to:
- Increase strongly
- Decrease strongly (Correct answer)
- Stay the same
- Increase weakly
Correct answer: Decrease strongly
A correlation of -0.92 indicates a strong negative relationship, meaning as one variable rises, the other reliably decreases.
Question 7: A school reports that the average class size is 28 students, but half of all classes have 20 or fewer students. This suggests the distribution of class sizes is:
- Symmetrical
- Negatively skewed
- Uniform
- Positively skewed (Correct answer)
Correct answer: Positively skewed
When the mean (28) is higher than the median (≤20), the distribution has a right (positive) skew caused by a few very large classes pulling the mean up.
CSET Data Analysis & Reporting 5
A district administrator notices that the mean SAT score increased from 1050 to 1080 after implementing a new curriculum.
To determine if this change is statistically significant, the administrator should: