MATH 221 Week 3 Homework; Statistics for Decision-Making

1. Question: Let x represent the number of pets in pet stores. This would be considered what type of variable: 2. Question: Let x represent the number of players on a sports field. This would be considered what type of variable? 3. Question: Consider the following table. If you created the probability distribution for these data, what would be the probability of 30-39? 4. Question: Consider the following table. Find the mean of this variable. 5. Question: Consider the following table. Find the variance of this variable. 6. Question: Consider the following table. Find the standard deviation of this variable. 7. Question: The standard deviation of video game A’s outcome is 1.8940, while the standard deviation of video game B’s outcome is 1.6179. Which game would you likely to chose if you wanted players to have the most choice and why? 8. Question: Ten frequent gamers are randomly selected. The random variable represents the number of frequent gamers who play video games on their smart phones. For this to be binomial experiment what assumption need to be made? 9. Question: A survey found that 31% of all teens buy soda (pop) at least once each week. Seven teens are randomly selected. The random variable selected which represents number of teens who buy soda (pop) at least once each week. What is the value of n? 10. Question: Thirty-five% of US adults have little confidence in their cars. You randomly select five US adults. Find the probability that the number of US adults have little confidence in their cars is (1) exactly six and find the probability that it is (2) more than 7. 11. Question: Say a business found that 29.5% of customers in Washington prefer grey suits. The company chooses 8 customers in Washington and asks them if they prefer grey suits. What assumption be made for this study to follow the probabilities of a binomial experiment? 12. Question: Seven baseballs are randomly selected from a production line to see if their stitching is straight. Over time the company has found that 89.4% of all baseballs have straight stitching. If exactly seven of five have straight stitching, should the company stop the production line? 13. Question: A soup company puts 20 ounces of soup in each can. The company has determined that 97% of the cans have correct amount. Which of the following describes a binomial experiment that would determine the probability that a case of 24 cans has all cans that are properly filled? 14. Question: A supplier must create metal roads that are 2.1 inches width to fix into the next step of production. Can a binomial experiment be used to determine the probability that the roads are too wide, too narrow or about right? 15. Question: In a box of 12 tape measures, there is one that does not work. Employees take tape measure as needed and returned after use. You are the 9th employee to take a tape measure. Is this a binomial experiment? 16. Question: Eighty-two% of workers make judgments about their co-workers based on the cleanliness of their desk. You randomly select seven 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 on the cleanliness. Which outcome of this binomial experiment would be considered unusual? 17. Question: Ninety-one% of products come off the line within product specifications. Your quality control department selects 15 products 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) and repaired? 18. Question: The probability of a potential employee passing a drug test is 90%. If you select 11 potential employees and gave them a drug test, how many would you expect to pass the test? 19. Question: The probability of a potential employee passing a training course is 86%. If you select 15 potential employees and gave them the training course, what is the probability that more than 11 will pass the test? 20. Question: Off the production line there is a 3.7% chance that a candle is defective. If the company selected 45 candles off the line, what is the probability that fewer than 3 would be defective?