40 ❯ STEP 2. Determine Your Test Readiness
involved in reading and comprehension. Broca’s area in the frontal lobe controls the pro-
duction of speech and language. The angular and supramarginal gyri link different parts
of the brain so that letter shapes can be interpreted and combined to form words. The
temporal lobe is responsible for phonological awareness for decoding and discriminating
sounds. Damage to any one of these areas during a car accident will result in difficulty read-
ing. Damage to the eyes, cornea, lens, or optic nerve might create visual disturbances which
will also lead to difficulty reading. Damage to Wernicke’s area located in the temporal lobe
will result in a victim’s inability to comprehend language, making it difficult to understand
what others are saying.
To determine if a chemical were to cause similar symptoms in an industrial facility, a
researcher would conduct an experiment in which sample employees would be divided into
two groups, the research population. One group would be exposed to the chemical in ques-
tion and the other would not, acting as the experimental and control groups, respectively.
Since the target population, or the entire roster of employees, is probably too large to inves-
tigate, the researcher would select a portion of the employees as the experimental or research
population. All employees of the company would have an equal chance of being selected
for the experiment. The researcher might choose to use every 4th person who reports to
work on a single day as the selection criteria. Random assignment would also be utilized
to place participants into the experimental or control group. Random selection is essential
to external validity, or the extent to which the researcher can use the results of the study to
generalize to the larger population. Random assignment is necessary for internal validity,
which allows the researcher to make causal claims about the effect of the chemical. Both the
experimental and control groups would be given specific tasks to perform, such as reading
a passage and responding to comprehension questions, assembling a puzzle, or other fine
motor skill tasks. The researcher will collect data based on scores, time for completion, and/
or accuracy. The employees assigned to the experimental group would conduct their tasks
while being exposed to the chemical in question. Those in the control group would work
in an environment clean of any chemicals. Data on the results of the performance by two
groups will be collected and compared.
The researcher should be aware of the potential for any illusory correlations, or those
events that appear to be related in which, in fact, no relationship exists. The evidence may sug-
gest that the presence of a particular chemical has caused the headaches, dizziness, and other
symptoms, but it may be due to other factors. One can state that there is a particular chemical
present in the industrial building and that many employees have headaches. To state that the
chemical has caused the headaches requires experimental evidence. While presenting the data
collected from the experiment, the correlation coefficient will indicate how closely the symp-
toms are related to the presence of the chemical. A strong relationship will have a coefficient
value closer to 1.0. A negative correlation will indicate that as one variable increases, in this
experiment it would be the level of chemical, the other variable, in this case the symptoms,
would decrease. A positive correlation will indicate that as one variable increases, so does the
other. A strong positive correlation with a high positive coefficient will indicate a strong rela-
tionship between the presence of the chemical and the employees’ symptoms.
Confounding variables may pose a hurdle to the success of the researcher’s efforts. An
example of this may be employees having difficulty reading directions due to fatigue or eye
strain in the workplace. Headaches may be caused by the prevalence of loud noises or poor
lighting in the workplace rather than the chemical in question.
Any experiment using live subjects requires strict use of appropriate ethical guidelines.
Subjects should be made aware of the purpose of the experiment and what they could
expect to experience. This includes an understanding of the potential dangers that may
arise as a result of exposure to the chemical in question. Long-term effects of this exposure
might be unknown.