## MATH 221 Week 5 Quiz (Fall 2018)

**Question**: (CO 4) Consider the following table: ……..If you created the probability distribution for these data, what would … the probability of 50-59?**Question**: (CO 4) Consider the following table of hours worked by part-time employees. These employees must work in 5 hour blocks………Find the mean of this variable.**Question**: (CO 4) Consider the following table: …….. Find the variance of this variable.**Question**: (CO 4) Consider the following table: ……. Find the standard deviation of this variable.**Question**: (CO 4) Forty-nine percent of US teens have heard of a fax machine. You randomly select 12 US teens. Find the probability that the number of these selected teens that have heard of a fax machine is exactly six (answer listed below). Find the probability that the number is more than 8 (second answer listed below).**Question**: (CO 4) Ten rugby balls are … from the production line to see if their shape is correct. Over time, the company has found that 92.4% of all their rugby balls have the correct shape. If exactly 7 of the 10 have the right shape, should the company stop the production line?**Question**: (CO 4) A bottle of water is … to have 20 ounces. The bottling company has determined that 98% of bottles have the correct amount. Which of the following describes a binomial experiment that would determine the probability that a case of 36 bottles has all bottles properly filled?**Question**: (CO 4) On the production line the company finds that 99.7% of products are made correctly. You are responsible for quality control and take batches of 30 products from the line and test them. What number of the 30 being ly made would cause you to shut down production?**Question**: (CO 4) The probability of someone ordering the daily special is 52%. If the restaurant expected 65 people for lunch, how many would you expect to order the daily special?**Question**: (CO 4) Fifty-seven percent of employees make judgements about their co-workers based on the cleanliness of their desk. You randomly select 8 employees and ask them if they judge co-workers based on this criterion. The random variable is the number of employees who judge their co-workers by cleanliness. Which outcomes of this binomial distribution would … considered unusual?**Question**: (CO 4) Sixty-five percent of products come off the line ready to ship to distributors. Your quality control department selects 12 products randomly from the line each hour. Looking at the binomial distribution, if fewer than how many are within specifications would require that the production line … shut down (unusual) and repaired?**Question**: (CO 4) Out of each 100 products, 93 are ready for purchase by customers. If you selected 27 products, what would … the expected (mean) number that would … ready for purchase by customers?**Question**: (CO 4) Sixty percent of adults have looked at their credit score in the past six months. If you select 31 customers, what is the probability that at least 25 of them have looked at their score in the past six months?**Question**: (CO 4) One out of every 92 tax returns that a tax auditor examines requires an audit. If 50 returns are selected at random, what is the probability that less than 2 will need an audit?**Question**: (CO 4) Thirty-eight percent of consumers prefer to purchase electronics online. You randomly select 16 consumers. Find the probability that the number who prefer to purchase electronics online is at most 4.**Question**: (CO 5) The speed of cars on a stretch of road is normally … with an average 40 miles per hour with a standard deviation of 5.9 miles per hour. What is the probability that a randomly selected car is violating the speed limit of 50 miles per hour?**Question**: (CO 5) A survey indicates that shoppers spend an average of 22 minutes with a standard deviation of 16 minutes in your store and that these times are normally …. Find the probability that a randomly selected shopper will spend less than 20 minutes in the store.**Question**: (CO 5) The monthly utility bills in a city are normally … with a mean of $121 and a standard deviation of $23. Find the probability that a randomly selected utility bill is between $115 and $130.**Question**: (CO 5) A restaurant serves hot chocolate that has a mean temperature of 175 degrees with a standard deviation of 6.2 degrees. Find the probability that a randomly selected cup of hot chocolate would have a temperature of less than 166 degrees. Would this outcome warrant a replacement cup (meaning that it would … unusual)?**Question**: (CO 5) The yearly amounts of carbon emissions from cars in Belgium are normally … with a mean of 13.9 gigagrams per year and a standard deviation of 3.5 gigagrams per year. Find the probability that the amount of carbon emissions from cars in Belgium for a randomly selected year are between 11.5 gigagrams and 14.0 gigagrams per year.**Question**: (CO 5) On average, the parts from a supplier have a mean of 97.5 inches and a standard deviation of 6.1 inches. Find the probability that a randomly selected part from this supplier will have a value between 85.3 and 109.7 inches. Is this consistent with the Empirical Rule of 68%-95%-99.7%?**Question**: (CO 5) A process is normally … with a mean of 104 rotations per minute and a standard deviation of 8.2 rotations per minute. If a randomly selected minute has 80 rotations per minute, would the process … considered in control or out of control?**Question**: (CO 5) The soup produced by a company has a salt level that is normally … with a mean of 5.4 grams and a standard deviation of 0.3 grams. The company takes readings of every 10th bar off the production line. The reading points are 5.8, 5.9, 4.9, 5.7, 5.0, 4.9, 5.5, 5.1, 5.7, 6.1. Is the process in control or out of control and why?**Question**: (CO 5) The blenders produced by a company have a normally … life span with a mean of 8.2 years and a standard deviation of 1.3 years. What warranty should … provided so that the company is replacing at most 10% of their blenders sold?**Question**: (CO 5) A puck company wants to sponsor the players with the 10% quickest goals in hockey games. The times of first goals are normally … with a mean of 12.56 minutes and a standard deviation of 4.91 minutes. How fast would a player need to make a goal to … sponsored by the puck company?**Question**: (CO 5) A stock’s price fluctuations are approximately normally … with a mean of $104.50 and a standard deviation of $23.62. You decide to purchase whenever the price reaches its lowest 10% of values. What is the most you would … willing to pay for the stock?**Question**: (CO 5) The times that customers spend in a book store are normally … with a mean of 39.5 minutes and a standard deviation of 15.9 minutes. A random sample of 25 customers has a mean of 36.1 minutes or less. Would this outcome … considered unusual, so that the store should reconsider its displays?**Question**: (CO 5) The weights of ice cream cartons are normally … with a mean weight of 20 ounces and a standard deviation of 0.3 ounces. You randomly select 40 cartons. What is the probability that their mean weight is greater than 20.06 ounces?**Question**: (CO 5) Recent test scores on the Law School Admission Test (LSAT) are normally … with a mean of 162.4 and a standard deviation of 15.9. What is the probability that the mean of 12 randomly selected scores is less than 161?**Question**: (CO 5) The mean annual salary for intermediate level executives is about $74000 per year with a standard deviation of $2500. A random sample of 50 intermediate level executives is selected. What is the probability that the mean annual salary of the sample is between $71000 and $73500?

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