Jared is conducting an experiment with ESP (extrasensory perception) training. He begins with a pretest of his 40 participants a
nd divides them into two groups based on their scores. The participants with the 20 lowest scores are given extensive training on how to detect the signals. The participants with the 20 highest scores are given no training. Both groups are retested and the average score of the participants with the training improved. Why can't Jared conclude that the training caused the difference? a. testing effect
Testing effect is a type of threat to internal validity of an experiment. Internal validity is assessing whether a factor makes a difference in an experiment or not and if it does, whether there is adequate evidence to support this correlation.
Testing as a threat to internal validity is when a second test is taken on the outcome of a first test. Other internal validity threats are history, maturation, instrument modifications.
Answer: The correct answer is : The central limit theorem
Explanation: This is a fundamental theorem of probability and statistics. When the sample size is large enough, the distribution of the means follows approximately a normal distribution. The theorem can be applied regardless of the form of population distribution.
<span>Soccer academies in Spanish-speaking countries are mainly geared toward B. professional soccer players. They can advance even further in these academies and be sold to many teams who have enough money to pay for this addition to their team. </span>
