12 questions on Statistics for the Sciences with answers | MATH 3339, Exams of Statistics

Download 12 questions on Statistics for the Sciences with answers | MATH 3339 and more Exams Statistics in PDF only on Docsity! NAVIGATION [5] Q 1 [5] Q 2 [5] Q 3 [5] Q 4 [5] Q 5 [0] Q 6 [0] Q 7 [0] Q 8 [0] Q 9 [0] Q 10 [0] Q 11 [0] Q 12 TEST INFORMATION Your Score is: 20 Out of: 25 Time Allowed: 75 min Total Problems: 12 COLORING LEGEND Not Answered Incorrect Correct You scored 20 out of 25 Question 1 Your answer is CORRECT. A random sample of 64 observations produced a mean value of 78 and standard deviation of 7.5. The 95% confidence interval for the population mean μ is between a) 76.163 and 79.838 b) 76.458 and 79.542 c) 74.163 and 81.838 d) 76.663 and 79.338 e) 75.663 and 80.338 Question 2 Your answer is CORRECT. A random sample of 144 observations produced a sample proportion of 0.3. An approximate 95% confidence interval for the population proportion p is between a) 0.262 and 0.338 b) 0.225 and 0.363 c) 0.225 and 0.375 d) 0.211 and 0.389 e) 0.237 and 0.363 Question 3 Your answer is INCORRECT. Which of the following statements are not true in developing a confidence interval for the population mean? a) The width of the confidence interval becomes narrower when the sample size n increases. b) The width of the confidence interval becomes wider as the confidence level increases. c) The width of the confidence interval becomes narrower when the sample mean increases.(Correct answer ;stupid mistake) d) All of the above statements are true. e) None of the above statements are true. Question 4 Your answer is CORRECT. A __________ error consists of rejecting the null hypothesis H0 when H0 is true. a) Type I b) Type II c) Power Question 5 Your answer is CORRECT. If the P-value is smaller than the level of significance α, then the researcher should __________ at level α. a) Reject H0 b) Accept H0 c) Fail to reject H0 Question 6 Your answer is CORRECT. This is a written question, worth 5 points. DO NOT place the problem code on the answer sheet. A proctor will fill this out after exam submission. Show all steps (work) on your answer sheet for full credit. Problem Code: 642 The length of needles produced by a machine has standard deviation of 0.02 inches. Assuming that the distribution is normal, how large a sample is needed to determine with a precision of ±0.005 inches the mean length of the produced needles to 95% confidence? a) I have placed my work and my answer on my answer sheet. b) I want to have points deducted from my test for not working this problem. Question 7 Your answer is CORRECT. This is a written question, worth 12 points. DO NOT place the problem code on the answer sheet. A proctor will fill this out after exam submission. Show all steps (work) on your answer sheet for full credit. Problem Code: 761 At the bakery where you work, loaves of bread are supposed to weigh 1 pound, with standard deviation σ = 0.13 pounds. You believe that new personnel are producing loaves that are heavier than 1 pound. As supervisor of Quality Control, you want to test your hypothesis where α = 0.05. You weigh 23 loaves and obtain a mean weight of 1.05 pounds. Part a: State your null and alternative hypotheses.