MATH 221 Week 3 Quiz

1. Question: (CO 3) Consider the following table: If you created the probability distribution for these data, what would be the probability of 50-59? 2. Question: (CO 3) Consider the following table of hours worked by part- time employees. These employees must work in 5 hourblocks. Find the mean of this variable. 3. Question: (CO 3) Consider the following table: Find the variance of this variable. 4. Question: (CO 3) Consider the following table: Find the standard deviation of this variable. 5. Question: (CO 3) Forty-three 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 (first answer listed below). Find the probability that the number is more than 8 (second answer listed below). 6. Question: (CO 3) Ten rugby balls are randomly selected 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 thecorrectshape.Ifexactly7ofthe10havetherightshape, should the company stop the production line? 7. Question: (CO 3) A bottle of water is supposed to have 20 ounces. The bottling company has determined that 98% of bottles have the correct amount. Which of the following describes a binomialexperimentthatwoulddeterminetheprobabilitythat a case of 36 bottles has all bottles properly filled? 8. Question: (CO 3) 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 andtestthem.Whatnumberofthe30beingincorrectlymade would cause you to shut down production? 9. Question: (CO 3) The probability of someone ordering the daily special is 52%. If the restaurant expected 105 people for lunch, how many would you expect to order the daily special? 10. Question: (CO 3) Forty-seven percent of employees make judgments 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 be consideredunusual? 11. Question: (CO 3) 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 be shut down (unusual) andrepaired? 12. Question: (CO 3) Out of each 100 products, 93 are ready for purchase by customers. If you selected 27 products, what would be the expected(mean)numberthatwouldbereadyforpurchaseby customers? 13. Question: (CO 3) Sixty percent of adults have looked at their credit score in the past six months. If you select 31 customers, what istheprobabilitythatatleast25ofthemhavelookedattheir score in the past six months? 14. Question: (CO 3) 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? 15. Question: (CO 3) Thirty-eight percent of consumers prefer to purchase electronics online. You randomly select 16 consumers. Find the probability that the number who prefer topurchase electronics online is at most 3. 16. Question: (CO 3) In the morning, about 25% of adults know what they will have for dinner. If one morning, you ask 22 adults if they know what they will have for dinner, what is the probability that more than 8 will sayyes? 17. Question: (CO 3) Among teenagers, 73% prefer watching shows over the internet, rather than through cable. If you asked 104 teenagers if they preferred watching shows over the internet, rather than through cable, how many would you expect to sayyes? 18. Question: (CO 3) Sixty-four percent of those that use drive through services believe that the employees are at least somewhat rude. If you asked 87 people who use drive through services if they believe that the employees are at leastsomewhatrude, what is the probability that at most 60 sayyes?