Subject: Probability and Statistics

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Topics: Normal Random Variable

Direction: Choose the correct answer for the following questions:

Page 276-277 Item no. 3: When do we consider that the sample size is small? A. when it is less than 30 B. when it is between 20 to 40 C. when it is greater than 25 but less than 40 D. when it is only 1% of the total population Page 276-277 Item no. 4: In Student's t-distribution, what is the sample size if the degree of freedom is 25? A. 5 B. 24 C. 25 D. 26 Page 276-277 Item no.5: What is the difference between the normal distribution and the t-distribution? A. The t-distribution has a lower peak. B. The t-distribution is centered at 0. C. The t-distribution is symmetric in the middle. D. The t-distribution has tails that asymptotic to the horizontal axis Page 291-292 Item no. 1: It is a value in the t-distribution that is less than the probability of the given percentage. A. degrees of freedom C. t-value B. percentile D. right-tailed value Page 291-292 Item no. 2: If the area of the unshaded part of the tdistribution is 0.85. what is the area of the shaded region? A. 0.15 B. 0.75 C. 0.85 D. 85% Page 291-292 Item no. 3: If the given t-value is 2.056 and the shaded region is on the right of the tdistribution with 26 degrees of freedom. what is the area of the unshaded region? A. 0.025 B. 0.15 C. 0.95 D. 0.975 Page 291292 Item no. 4: What is the area on the left tail of the t-distribution with 14 degrees of freedom corresponding to tvalue of 3.787? A. 0.001 B. 0.01 C. 0.975 D. 0.999 Page 300-302 Item no. 7: For nos. 7 - 10: A survey of 200 Senior High School learners shows that they read on average 18.5 hours per week with a margin of error of 2.2 hours at a 95% confidence level. What is the sample mean? A.200 B. 18.5 C. 15.7 D. 2.2 Page 300-302 Item no. 8: Which of the following values is the margin of error? A.15.7 B. 2.2 C. 0.95 D. 0.05 Page 300-302 Item no. 9: Which of the following intervals is the confidence interval? A. (18.5. 17.9) B. (16.3. 20.7) C. (135.179) D. (14.75.16.65) Page 300-302 Item no. 10: What is the upper limit of the interval? A. 16.3 B. 17.9 C. 18.7 D. 20.7 Page 312-314 Item no. 7: (for items. 7 8) Edward owns a meat store and he wants to find out the average amount of his daily sale. He randomly recorded his sales for 16 days and found the average to be P 8,500. It is known from last years record that the standard deviation of his sales is 9150 and a 99% level of confidence is to be used. What is the sampling size in the given problem? A. 150 B. 100 C. 50 D. 16 Page 312-314 Item no. 8: What is the margin of error for his estimate? A. 96.75 B. 58.7 C. 48.7 D. 38.7 Page 312-314 Item no. 9: Given: n= 200, = 35, and a 96% confidence level. Which of the following values is the length of the confidence interval? A. 10.15 B. 14.54 C. 15.23 D. 18.25 Page 312-314 Item no. 10: Given a sample size of 125 and a population standard deviation of 88 having an 80% level of confidence. Which of the following values is the length of the confidence interval? A. 16.15 B. 18.15 C. 20.15 D. 24.15 Page 324-325 Item no. 5: What is the given confidence level? A. 99% C. 0.01 B. 0.10 D. 0.05 Page 324-325 Item no. 6: What is a? A. 95% C. 0.01 B. 0.10 D. 0.05 Page 334-336 Item no. 12: What is the desired margin of error for the estimate of the population parameter? A.2B.3C.4D.16 Page 334-336 Item no. 13: What sample size shall be used by a researcher to meet the expected results? (Round up to the nearest whole number) A. 16 B. 32 C. 62 D. 107