Jared is conducting an experiment with extrasensory perception (ESP) training. He begins with a pretest of his 40 participants and then divides them into two groups based on their scores. The participants with the 10 lowest scores are given extensive training on how to detect the signals. The participants with the 30 highest scores are given no training. Both groups are retested and the average score of the participants with the training improved, whereas the average score of the participants without the training fell. Which threat to internal validity should Jared consider?

regression threat

Explanation:

Internal validity is a measure of how the conditions of an experiment makes a difference and whether there is enough evidence to come to a vivid conclusion. There are several threats to internal validity, which include, history, testing, instrumentation, subject selection, selection maturity, and regression. Regression threat is also called regression to the mean. The main cause of this threat is selecting subjects based on extreme scores or characteristics, as the case may be in the example. Jared selected participants with extreme scores.

b) to encourage free trade

levels of production can be increased by technology while holding labor and capital constant, because increased technology makes the production process more efficient. subsequently, the lras curve is almost a vertical line, that can shift to the right, with an increase in technology.

the relationship between the lras curve and the ppc is that both can make the economy could grow. the ppc achieves that when it shifts outward because of more resources or technological advances while the lras curve shifts if more resources are developed or if there are technological advances.

the lras curve is a vertical line at an output level that represents the number of goods and services a nation can produce over a sustained period using all of its productive resources as efficiently as possible with all of the current technology available to it.

the production possibilities frontier (ppf) is a graphical device that is used for economic analysis of production decisions because the ppf measures the maximum possible combinations of two goods that an economy is capable of producing with its currently available resources and technology.