An experimenter is interested in the influence of taking a one-semester-long test preparation course on performance on the Scholastic Aptitude Test (SAT). She contacts high school students who have and who have not taken the course and compares their scores on the SAT exam. She finds that the students who have taken the course score significantly higher on the test. Which of the following represents the principal threat to the internal validity of this experiment?
a. Regression to the mean
b. Maturation
c. Selection
d. Attrition
Question 2
An experimenter is interested in the influence of taking a one-semester-long test preparation course on performance on the Scholastic Aptitude Test (SAT). She contacts high school students who have and who have not taken the course and compares their scores on the SAT exam. She finds that the students who have taken the course score significantly higher on the test. The appropriate statistical test is
a. descriptive statistics.
b. Pearson correlation.
c. chi-square.
d. one-way ANOVA.
Influence of abiotic factors on competition between T. castaneum and T. confusum.
A medical assistant labels the allergens for a patch test.
If the gauge reading is now much higher than the first test results, then the cause of the low ...
Induration measurement in a tuberculin skin test, a type IV hypersensitivity.
Gingival enlargement in a patient taking phenytoin.
Uncover the back down to the waist. Stand at the head to apply lubricant to the back using long ...