The distribution of IQ scores for high school graduates is normally distributed with mean 400 and standard deviation 80. (i) What is the 90th percentile of this distribution of the IQ scores? (ii) Find the IQ scores that form the boundaries of the middle 60% of the distribution of the scores. (iii) What is the probability that a randomly selected score exceeds 375? (Round your answer to 4 decimal places)
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Sri K.
Question # 2 (Total marks: 15) (a) The distribution of IQ scores for high school graduates is normally distributed with mean 400 and standard deviation 80. (i)| What is the 90th percentile of this distribution of the IQ scores? (3 marks) (ii) Find the IQ scores that form the boundaries of the middle 60% of the distribution of the scores. (4 marks) (iii) What is the probability that a randomly selected score exceeds 375? 3 marks) (Round your answer to 4 decimal places) (b) An airline finds that 5% of the persons making reservations on a certain flight will not show up for the flight. If the airline sells 160 tickets for a flight that has only 155 seats, what is the probability that a seat will be available for every person holding a reservation and planning to fly? (5 marks)
The distribution of IQ scores forms a normal distribution with a mean of 100 and a standard deviation of 15. A. If we take random samples of 9 students, what range of values can be expected for the sample mean 60% of the time? (4 pts) B. What are the boundaries of the middle 75 percent of all possible random samples of 25 students for this distribution? (4 pts)
Adi S.
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