The scores of high school seniors on the ACT college entrance examination in 2003 were normally distributed with a mean of 20.8 and a standard deviation of 4.8. What is the probability that a random student taking the test in 2003 had a score above 25.67? What is the 90th percentile for ACT scores in 2003? What is the probability that a random group of students had a mean score above 25.6?
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Probability of a random student scoring above 25.67: We need to find the area under the normal distribution curve to the right of 25.67. We can use a standard normal distribution table or a calculator to find the z-score corresponding to 25.67. z = (25.67 - Show more…
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