MATH 221 Week 3 Homework

1. Question: Let x represent the height of first graders in a class. This would be considered what type of variable: 2. Question: Let x represent the height of corn in Oklahoma. 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 18-29? 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: Fifteen golfers are randomly selected. The random variable represents the number of golfers who only play on the weekends. For this to be a binomial experiment, what assumption needs to be made? 8. Question: A survey found that 75% of all golfers play golf on the weekend. Eighteen golfers are randomly selected. The random variable represents the number of golfers that play on the weekends. What is the value of p? 9. Question: Thirty-five percent of US adults have little confidence in their cars. You randomly select ten US adults. Find the probability that the number of US adults who have little confidence in their cars is (1) exactly six and then find the probability that it is (2) more than 7. 10. Question: Eleven baseballs are randomly selected from the production line to see if their stitching is straight. Over time, the company has found that 98.3% of all their baseballs have straight stitching. If exactly nine of the eleven have straight stitching, should the company stop the production line? 11. Question: A supplier must create metal rods that are 16.4 inches long to fit into the next step of production. Can a binomial experiment be used to determine the probability that the rods are too long, too short, or about right? 12. Question: In a box of 12 tape measures, there is one that does not work. Employees take tape measures as needed and returned after use. You are the 9th employee to take a tape measure. Is this a binomial experiment? 13. Question: Forty-two percent of employees make judgements about their co-workers based on the cleanliness of their desk. You randomly select 7 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 considered unusual? 14. Question: The probability of a potential employee passing a drug test is 86%. If you selected 15 potential employees and gave them a drug test, how many would you expect to pass the test? 15. Question: Off the production line, there is a 2.2% chance that a candle is defective. If the company selected 40 candles off the line, what is the standard deviation of the number of defective candles in the group?