You are a policy maker who is concerned with low standardized-test scores in high schools in your school district. You are interested in understanding whether offering special test preparation classes to the students could potentially improve these scores. Towards that end, you randomly select 10 schools and measure the average standardized-test score for these high schools, which turns out to be 69. You randomly select another sample of 10 schools and find that the average score in this sample is 70. As a next step, you offer test preparation classes in the schools in the first group. After 6 months, you find that the score now stands at 78. In the second group, where no test preparation classes are offered, the score after 6 months was recorded at 71. What is the estimated impact of the experiment of offering test preparation classes?a.1b.7c.8d.9

In a test for esp (extrasensory perception), the experimenter looks at cards that are hidden from the subject. each card contains either a star, a circle, a wave, a cross or a square.(five shapes) as the experimenter looks at each of 20 cards in turn, the subject names the shape on the card. when the esp study described above discovers a subject whose performance appears to be better than guessing, the study continues at greater length. the experimenter looks at many cards bearing one of five shapes (star, square, circle, wave, and cross) in an order determined by random numbers. the subject cannot see the experimenter as he looks at each card in turn, in order to avoid any possible nonverbal clues. the answers of a subject who does not have esp should be independent observations, each with probability 1/5 of success. we record 1000 attempts. which of the following assumptions must be met in order to solve this problem? it's reasonable to assume normality 0.8(1000), 0.2(1000)%30 approximately normal 0.8(1000), 0.2(1000)% 10 approximately normal srs it is reasonable to assume the total number of cards is over 10,000 it is reasonable to assume the total number of cards is over 1000