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You Are Evaluating Investing in a Cognitive Training Company

question 42

Multiple Choice

You are evaluating investing in a cognitive training company.For this reason, you want to determine whether users who complete at least 75% of the recommended daily training for two months show improved levels of reading comprehension and problem-solving skills.You select a random sample of new users and get test scores for each participant in the sample.The test score is a composite of reading comprehension and problem-solving skills.Two months later, you randomly select 15 users from the original sample who have completed 75% or more of the recommended training in the last two months and have them take a test similar to the initial test.You are interested in determining whether the average test score before training is different than the average test score after training for this sample.The after-training average is 92.8, which is 2.7 points higher than the before-training average.The sample standard deviation of the differences is 1.2.You can assume that the differences are normally distributed in the population.The degrees of freedom for this test are ______.

Definitions:

Ex Vivo

A term referring to biological experiments done outside of a living organism, often in a controlled laboratory environment.

Genetically Modified

Pertains to organisms whose genetic material has been altered using genetic engineering techniques, often to introduce desirable traits.

Adenovirus Vector

A tool derived from adenovirus used in gene therapy and vaccines that delivers genetic material into cells to combat diseases.

In Vivo

Experiments or studies carried out within a living organism.