Ohio Grade 8 Achievement Test for Science – May 2008
Annotated Item 38
Standard and Benchmark Assessed:
Standard:
Scientific Ways of Knowing
Benchmark:
A. Use skills of scientific inquiry processes (e.g., hypothesis, record keeping,
description and explanation).
Multiple Choice Question:
Use the information below to answer questions 36 – 38.
Extinction
A paleontologist was studying the evidence of extinction of organisms in the fossil record.
Data were collected at several work sites. The paleontologist developed the drawing
below of eight layers at one work site. Other data used included the graph below that
shows changes in sea level from 490 million years ago to 60 million years ago. Asterisks on the
graph indicate times of mass extinction of marine organisms.
Source: Ohio Department of Education
July 08
Ohio Grade 8 Achievement Test for Science – May 2008
Annotated Item 38
38. The paleontologist examined 10 sites in all. She made detailed drawings of these sites and
removed sample fossils. She labeled the sample fossils with the site number, location and layer
in which the fossil was found. The paleontologist returned to the lab and discovered that some
of the fossil samples were missing labels. In your Answer Document, describe two different
ways the lack of labels for these samples will affect the interpretation of the data. (2 points)
Commentary:
This short answer question asks students to provide examples of how incomplete data from an
investigation makes it difficult to draw conclusions about the experimental results. Students are
provided information about an investigation including missing labels for fossil samples.
Students must recognize that in order to make scientifically valid conclusions about the fossils
the scientist needs scientifically accurate records. Students could suggest that the
incompleteness of the data will mean the scientist will have a smaller sample size for the
investigation. For example, students could state that for the samples without labels, the
paleontologist doesn’t know what site or what rock layer the sample came from. Without this
information it is difficult to interpret relative age and how the fossils may differ between sites.
The response that earns full credit describes how the incomplete data make it difficult to draw
conclusions about the experiment.
This question is classified as Demonstrating Investigation Processes of Science because the
task requires students to think scientifically based upon the given experimental context of what
to do with missing data.
Performance Data:
The percent of public school students earning each score point for question 38 on the May 2008
Grade 8 Achievement Test:
Source: Ohio Department of Education
July 08
Ohio Grade 8 Achievement Test for Science – May 2008
Annotated Item 38
Percent at Each Score Point
0
1
2
40%
27%
30%
Scoring Guidelines:
Scoring Guidelines
Exemplar Response:
The data for the samples without labels cannot be used because the paleontologist
doesn't know where they came from. All the interpretation of the fossils must be based
on only the fossils with labels (fewer samples).
Other Correct Response(s):
For the samples without labels, the paleontologist doesn't know what site or what rock
layer the sample came from. Without this information it is difficult to interpret relative age
and how the fossils may be different between sites.
Possible ways interpretation of the data will be affected:
• original site location of the samples is unknown
• original layer location of the samples is unknown
• relative age of the samples with missing labels cannot be estimated
• sequence of organisms through time may not be determined
• difference in appearance of organisms between sites may not be determined
• small sample size because of fewer labeled fossils
Points
Student Response
2 point text
The response clearly describes two ways that the data
interpretation will be affected.
1 point text
The response clearly describes one way that the data
interpretation will be affected.
1 point sample answer:
The paleontologist doesn't know where each sample came
from.
0 point text
The response fails to demonstrate any understanding as to
how the data interpretation will be affected if labels are missing.
The response does not meet the criteria required to earn one
point. It may only repeat information given in the test item. The
response may provide an incorrect solution/response and the
provided supportive information may be totally irrelevant to the
item, or possibly, no other information is shown. The student
may have written on a different topic or written, “I don't know”.
0 point sample answer:
They will use the samples that are labeled.
Keywords: data, sample size, scientific inquiry
Source: Ohio Department of Education
July 08