STAT200 Homework for week 5 Question 1 Every applicant for the open position took a test. Results of the test are close to the Normal distribution with mean = 200 and standard deviation =50. Company decided to call for interview applicants who's test score is on the top 20%. What should be the minimum test score to be called for an interview? Problem 2. Compute the 90% confidence interval for population mean based on the following sample data: 10, 17, 23, 26, 29, 30, 32, 33. Problem 3. A sample mean is x = 120 and sample size is n = 51. Estimate Confidence Interval for the population mean with Confidence Level 99% in two cases: Case A: The standard deviation of the population is known, =20. Tip: use z-factor from the Normal Distribution Table. Case B: The standard deviation of the population is unknown, but the sample standard deviation is given s=30. Tip: use t-factor from the t-Distribution Table. Problem 4. Random sample of 40 applicants showed that an average waiting time for load approval is x = 62 hours with a sample standard deviation s=24 hours. Use Confidence Level 95% to find Margin of Error and Confidence Interval for the population mean of waiting time. Problem 5. In a poll of n = 200 people has sample proportion of ps = 0.67. Compute a 90% confidence interval for the population proportion. 754L (0035-101013me TABLE A3 Degrees of Freedom 0.01 Appendix A t Distribution: Critical 1\" Values Area in One Tail 63.657 9.925 5.841 4.604 4.032 3.707 3.499 3.355 3.250 3.169 3.106 3.055 3.012 2.977 2.947 2.921 2.898 2.878 2.861 2.845 2.831 2.819 2.807 2.797 2.787 2.779 2.771 2.763 2.756 2.750 2.744 2.738 2.733 2.728 2.724 2.719 2.715 2.712 2.708 2.704 2.690 2.678 2.560 2.548 2.639 2.632 2.626 2.601 2.592 2.588 2.586 2.581 2.578 2.576 31.821 6.965 4.541 3.747 3.365 3.143 2.998 2.896 2.821 2.764 2.718 2.681 2.650 2.624 2.602 2.583 2.567 2.552 2.539 2.528 2.518 2.508 2.500 2.492 2.485 2.479 2.473 2.467 2.462 2.457 2.453 2.449 2.445 2.441 2.438 2.434 2.431 2.429 2.426 2.423 2.412 2.403 2.390 2.381 2.374 2.368 2.364 2.345 2.339 2.336 2.334 2.330 2.328 2.326 0.01 Area in 0.02 0.025 12.706 4.303 3.192 2.776 2.571 2.447 2.365 2.306 2.262 2229 2.201 2.179 2.160 2.145 2.131 2.120 2.110 2.101 2.093 2.086 2.030 2.074 2.069 2.064 2.060 2.056 2.052 2.045 9.045 2042 2.040 2.037 2.035 2.032 2.030 2.029 2.026 2.024 2.023 2.021 2.014 2.009 2.000 1.994 1.990 1.987 1.994 1.972 1.968 1.966 1.965 1.962 1.961 Two Taiis 0.05 0 0.05 0.10 .10 0.20 6.314 3.078 2.920 1.886 2.353 1.638 2.132 1.533 2.015 1.476 1.943 1.440 1.895 1.415 1.860 1.397 1.833 1.383 1.812 1.372 1.796 1.363 1.782 1.356 1.771 1.350 1.761 1.345 1.753 1.341 1.746 1.337 1.740 1.333 1.734 1.330 1.729 1.328 1.725 1.325 1.721 1.323 1.717 1.321 1.714 1.319 1.711 1.318 1.708 1.316 1.706 1.315 1.703 1.314 1.701 1.313 1.699 1.311 1.697 1.310 1.696 1.309 1.694 1.309 1.692 1.308 1.691 1.307 1.690 1.306 1.688 1.306 1.687 1.305 1.686 1.304 1.685 1.304 1.684 1.303 1.679 1.301 1.676 1.299 1.671 1.296 1.667 1.294 1.664 1.292 1.662 1.291 1.660 1.290 1.653 1.286 1.650 1.284 1.649 1.284 1.648 1.283 1.646 1.282 1.646 1.282 Le 1411 i C ri' 601' 7 value (negafive) Righf 1611 (I Crr'ficai 1' value iposr've) Two fan's 07/2 a/Z T i Crificcn' I value Criccn' f value (negative) (posifr'w)