7) Find the z-score for which the area under the standard normal curve is the following:...

 

 

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7) Find the z-score for which the area under the standard normal curve is the following: (a) To its right is 0.96 (b) To its right is 0.40 (c) To its left is 0.07 (d) That separates the bottom 80% from the top 20% 8) The board of examiners that administers the real estate brokers examination in a certain state found that the mean score on the test was 375 and the standard deviation was 36. If the board wants to set the passing score so that only the best 80% of all applicants pass, what is the passing score? Assume that the scores are normally distributed. 9) Suppose a population has a mean weight of 175 pounds and a standard deviation of 15 pounds. A sample of 100 items is drawn from this population. What is the standard error of the mean? 10) A random sample of size n is to be drawn from a population with = 600 and = 300. What size sample would be necessary to ensure a standard error of 20? 11) The amount of corn chips dispensed into a 16-ounce bag by the dispensing machine has been identified as possessing a normal distribution with a mean of 16.5 ounces and a standard deviation of 0.2 ounce. Suppose 100 bags of chips were randomly selected from this dispensing machine. Find the probability that the sample mean weight of these 100 bags exceeded 16.6 ounces. 12) Assume that blood pressure readings are normally distributed with a mean of 122 and a standard deviation of 6.4. If 64 people are randomly selected, find the probability that their mean blood pressure will be less than 124. 13) The owner of a computer repair shop has determined that their daily revenue has mean $6600 and standard deviation $500. The daily revenue totals for the next 30 days will be monitored. What is the probability that the mean daily revenue for the next 30 days will be between $6000 and $7000? 7) Find the z-score for which the area under the standard normal curve is the following: (a) To its right is 0.96 (b) To its right is 0.40 (c) To its left is 0.07 (d) That separates the bottom 80% from the top 20% 8) The board of examiners that administers the real estate brokers examination in a certain state found that the mean score on the test was 375 and the standard deviation was 36. If the board wants to set the passing score so that only the best 80% of all applicants pass, what is the passing score? Assume that the scores are normally distributed. 9) Suppose a population has a mean weight of 175 pounds and a standard deviation of 15 pounds. A sample of 100 items is drawn from this population. What is the standard error of the mean? 10) A random sample of size n is to be drawn from a population with = 600 and = 300. What size sample would be necessary to ensure a standard error of 20? 11) The amount of corn chips dispensed into a 16-ounce bag by the dispensing machine has been identified as possessing a normal distribution with a mean of 16.5 ounces and a standard deviation of 0.2 ounce. Suppose 100 bags of chips were randomly selected from this dispensing machine. Find the probability that the sample mean weight of these 100 bags exceeded 16.6 ounces. 12) Assume that blood pressure readings are normally distributed with a mean of 122 and a standard deviation of 6.4. If 64 people are randomly selected, find the probability that their mean blood pressure will be less than 124. 13) The owner of a computer repair shop has determined that their daily revenue has mean $6600 and standard deviation $500. The daily revenue totals for the next 30 days will be monitored. What is the probability that the mean daily revenue for the next 30 days will be between $6000 and $7000?