A professor knows that her statistics students' final exam scores have a mean of 80 and a standard deviation of 12.2. In her class, an "A" is any exam score of 90 or higher. This quarter she has 25 students in her class. What is the probability that 7 students or more will score an "A" on the final exam? Hint: You will need to use your knowledge of normal probability distributions to determine the probability of one individual getting an A and then use your knowledge of binomial distributions to determine the probability of 7 students or more out of 25 students getting an A. prob = ____________ Report your final answer accurate to 4 decimal places. Do not round any of the numbers in this calculation until the very end of the problem!
Continuous Probability Distributions
Probability distributions are of two types, which are continuous probability distributions and discrete probability distributions. A continuous probability distribution contains an infinite number of values. For example, if time is infinite: you could count from 0 to a trillion seconds, billion seconds, so on indefinitely. A discrete probability distribution consists of only a countable set of possible values.
Normal Distribution
Suppose we had to design a bathroom weighing scale, how would we decide what should be the range of the weighing machine? Would we take the highest recorded human weight in history and use that as the upper limit for our weighing scale? This may not be a great idea as the sensitivity of the scale would get reduced if the range is too large. At the same time, if we keep the upper limit too low, it may not be usable for a large percentage of the population!
A professor knows that her statistics students' final exam scores have a mean of 80 and a standard deviation of 12.2. In her class, an "A" is any exam score of 90 or higher. This quarter she has 25 students in her class. What is the
Hint: You will need to use your knowledge of normal probability distributions to determine the probability of one individual getting an A and then use your knowledge of binomial distributions to determine the probability of 7 students or more out of 25 students getting an A.
prob = ____________
Report your final answer accurate to 4 decimal places. Do not round any of the numbers in this calculation until the very end of the problem!
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