1. The reading speed of second grade students is approximately normal with a mean of 87 words per minute and a standard deviation of 10 words per minute. a) What is the probability that a randomly selected student will read more than 93 words per minute? b) What is the probability that a random sample of 12 second grade students results in a mean reading rate of more than 98 words per minute? c) There is a 5% chance that the mean reading speed of a random sample of 20 second grade students will exceed what value?
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z = (93 - 87) / 10 = 0.6 Using a standard normal distribution table or calculator, we can find that the probability of a z-score of 0.6 or higher is approximately 0.2743. Show more…
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