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1. (TCO 9) The hours of study and the final exam grades have this type of relationship: ? = 6.75(hours) + 37.45. Based on this linear regression equation, estimate the expected grade for a student spending 8 hours studying. Round your answer to two decimal places. (Points : 6) 91.45 54 93.42 89.45 2. (TCO 5) A company produces electronic equipments claims that 98% of their products never need any kind of maintenance. We selected 10 of their products and we wanted to know the probability that 8 of them never need maintenance. Choose the best answer of the following: (Points : 6) This is an example of a Poisson probability experiment This is an example of a Binomial probability experiment This is neither a Poisson nor a Binomial probability experiment Not enough information to determine the type of experiment 3. (TCO 5) Microfracture knee surgery has a 75% chance of success on patients with degenerative knees. The surgery is performed on 5 patients. Find the probability of the surgery being successful on more than 3 patients? (Points : 6) 0.487304 0.367188 0.632813 0.762695 4. (TCO 5) It has been recorded that 10 people get killed by shark attack every year. What is the probability of having 7 or 8 people get killed by shark attack this year? (Points : 6) 0.130141 0.202678 0.220221 0.797321 5. (TCO 2) The mode teaching hours for a full time faculty at a state university is eight hours per week. What does this tell you about the typical teaching hours for full time faculty at that university? (Points : 6) Half the full time faculties teach less than eight hours per week while half teaches more than eight hours per week. The average teaching hours for full time faculty is eight hours per week. More full time faculty teaches eight hours per week than any other number of teaching hours. The number of teaching hours for full time faculty in not very consistent because eight is such a low number. 6. (TCO 6) Assuming that the data are normally distributed with a mean of 45 and a standard deviation of 3.25, what is the z-score for a value of 40? (Points : 6) 1.54 2.38 -1.36 -1.54 7. (TCO 8) The mean hours of Internet usage by adults in the US in claimed to be less than 25 hours per week. A hypothesis test is performed at a level of significance of 0.05 with a P-value of 0.11. Choose the best interpretation of the hypothesis test. (Points : 6) Reject the null hypothesis; there is enough evidence to reject the claim that the mean of hours Internet usage by adults in the US is 25 hours. Reject the null hypothesis; there is enough evidence to support the claim that the mean hours Internet usage by adults in the US is 25 hours per week. Fail to reject the null hypothesis; there is not enough evidence to reject the claim that the mean hours of Internet usage by adults in the US is 25 hours per week. Fail to reject the null hypothesis; there is not enough evidence to support the claim that the mean hours of Internet usage by adults in the US is 25 hours per week. 8. (TCO 8) A result of an entry level exam reveals that 22% of students fail that exam. In a hypothesis test conducted at a level of significance of 2%, a P-value of 0.045 was obtained. Choose the best interpretation of the hypothesis test. (Points : 6) Fail to reject the null hypothesis; there is not enough evidence to reject the claim that 22% of students fail the entry level exam. Fail to reject the null hypothesis; there is not enough evidence to support the claim that 22% of students fail the entry level exam. Reject the null hypothesis; there is enough evidence to reject the claim that 22% of students fail the entry level exam. Reject the

null hypothesis; there is enough evidence to support the claim that 22% of students fail the entry level exam. 9. (TCO 2) You want to buy light bulbs and you want to choose between two vendors. Vendor A’s light bulbs have a mean life time of 800 hours and a standard deviation of 175 hours. Vendor B’s light bulbs also have a mean life time of 800 hours, but a standard deviation of 225 hours. You want light bulbs that have more life time consistency, which vendor will you purchase from? (Points : 6) Vendor A because you will be more likely get light bulbs with the same life time Vendor B because you will be more likely get light bulbs with the same life time Either one because both produce light bulbs with the same mean life time. Neither one because a mean height of 800 inches is too short for a light bulb. 10. (TCO 4) A jar contains balls of four different colors; red, blue, yellow and green. The total balls are divides as 45% red, 35% blue, 15% yellow, and 5% green. If you are to select one ball at random. Find the expected value of your winning amount if the payments are set to be $5, $15, $25, $60 for red, blue, yellow and green ball respectively. Winning amount 5 15 25 60 Probability 45% 35% 15% 5% (Points : 6) The expected winning amount is $28.50 The expected winning amount is $14.25 The expected winning amount is $25.50 The expected winning amount is $11.25 11. (TCO 3) The grades of 22 students are listed below. Use the stem & leaf to determine the shape of the distribution. Choose the best answer. 4 | 7 5 5 | 1 7 5 6 | 5 6 7 8 9 7 | 1 6 7 8 8 9 8 | 2 4 7 6 9 | 4 7 (Points : 6) The data is symmetric The data is skewed to the right The data is skewed to the left The data is bimodal 12. (TCO 1) A researcher is interested in studying people’s mean age in a certain region. If the population standard deviation is known to be 8 years and 1.5 year of error margin is allowed, find the minimum simple size the researcher needs to use, knowing that he is going to conduct his study using 95% confidence level. (Points : 6) Sample Size = 77 Sample Size = 25 Sample Size = 210 Sample Size = 110 13. (TCO 6) Horse race time is found to be normally distributed with a mean value of 18 minutes and a standard deviation of 4 minutes. Horses whose race time is in the top 6% will not be eligible to participate in a second round. What is the lowers race time that makes a horse losses his eligibility to participate in a second round? (Points : 6) 26.6 11.8 24.2 20.3 14. (TCO 5) A class containing 15 students 5 of them are females. In how many ways can we select a group of 4 male students? (Points : 6) 260 120 5040 210 15. (TCO 6) Research shows that the life time of Everlast automobile tires is normally distributed with a mean value of 60,000 miles and a standard deviation of 5,000 miles. What is the probability of having a tire that lasts more than 67,000 miles? (Points : 6) 0.9192 0.0808 1.40 0.0793 16. (TCO 10) A research shows that employee salaries at company XYX, in thousands of dollars, are given by the equation y-hat= 48.5 + 2.2 a + 1.5 b where ‘a’ is the years of experience, and ‘b’ is the education level in years. In thousands of dollars, predict the salary for an employee with 7 years experience and 12 years education level. (Points : 6) 52.2 81.9 67.5 63.9 17. (TCO 9) For the graph below, choose the statement that best describes the relationship between the variables. (Points : 6) As hours of absences increases, grades decreases. As hours of absences decreases, grades increases. As hours of absences increases, grades increases. There is no relationship between hours of absences and grades.