PROBLEM 1
According to statistics from the U.S. National Eye Institute, that 8% of Caucasian men and 0.5% of Caucasian women have some form of color vision deficiency (aka “color blindness”). Assume that women and men exist in equal number in the U.S. population.
- [5pt] What is the probability that a random person, X, from this population is color blind?
- [5pt] An eye doctor is seeing a Caucasian patient who is known to be color blind. Calculate the probability that this patient is male.
PROBLEM 2
Terpz4LYF produces clocks that count down the time until a Terp graduates from UMD. They market these clocks to alumni, who purchase the clock when a future Terp is born. Your parents purchased this clock for you! But is it reliable? Let’s find out.
The clock has a time to failure distribution given by the following:
Find:
- [5pt] The reliability of the clock at 21 years.
- [5pt] The MTTF of the clock.
- [5pt] The hazard rate function.
- [5pt] Do you consider this a reliable product? Explain why.
PROBLEM 3
You are given the following grouped data. Your supplier has told you that the failure times for this widget are normally distributed. You want to conduct a test to be sure. Use
| Failure time (days) | Number of failures | |
| Lower | Upper | |
| 0 | 50 | 7 |
| 50 | 75 | 11 |
| 75 | 100 | 14 |
| 100 | 200 | 10 |
| 200 | 300 | 8 |
- [10pts] Use the data to estimate the parameters of the normal distribution
- [10pts] Use a chi-squared test to test the hypothesis that these data come from a normal distribution with the parameters you estimated. Discuss the interpretation of the test.
Critical Values of Chi-Square Distribution Function
| α | ||||||||||
| ν | ||||||||||
| 1 | 0.0516 | 0.04393 | 0.03157 | 0.00393 | 0.0158 | 2.7055 | 3.8415 | 6.6349 | 7.8794 | 10.8276 |
| 2 | 0.0020 | 0.0100 | 0.0201 | 0.1026 | 0.2107 | 4.6052 | 5.9915 | 9.2103 | 10.5966 | 13.8155 |
| 3 | 0.0243 | 0.0717 | 0.1148 | 0.3518 | 0.5844 | 6.2514 | 7.8147 | 11.3449 | 12.8382 | 16.2662 |
| 4 | 0.0908 | 0.2070 | 0.2971 | 0.7107 | 1.0636 | 7.7794 | 9.4877 | 13.2767 | 14.8603 | 18.4668 |
| 5 | 0.2102 | 0.4117 | 0.5543 | 1.1455 | 1.6103 | 9.2364 | 11.0705 | 15.0863 | 16.7496 | 20.5150 |
| 6 | 0.3811 | 0.6757 | 0.8721 | 1.6354 | 2.2041 | 10.6446 | 12.5916 | 16.8119 | 18.5476 | 22.4577 |
| 7 | 0.5985 | 0.9893 | 1.2390 | 2.1673 | 2.8331 | 12.0170 | 14.0671 | 18.4753 | 20.2777 | 24.3219 |
| 8 | 0.8571 | 1.3444 | 1.6465 | 2.7326 | 3.4895 | 13.3616 | 15.5073 | 20.0902 | 21.9550 | 26.1245 |
| 9 | 1.1519 | 1.7349 | 2.0879 | 3.3251 | 4.1682 | 14.6837 | 16.9190 | 21.6660 | 23.5894 | 27.8772 |
| 10 | 1.4787 | 2.1559 | 2.5582 | 3.9403 | 4.8652 | 15.9872 | 18.3070 | 23.2093 | 25.1882 | 29.5883 |
| 11 | 1.8339 | 2.6032 | 3.0535 | 4.5748 | 5.5778 | 17.2750 | 19.6751 | 24.7250 | 26.7568 | 31.2641 |
| 12 | 2.2142 | 3.0738 | 3.5706 | 5.2260 | 6.3038 | 18.5493 | 21.0261 | 26.2170 | 28.2995 | 32.9095 |
| 13 | 2.6172 | 3.5650 | 4.1069 | 5.8919 | 7.0415 | 19.8119 | 22.3620 | 27.6882 | 29.8195 | 34.5282 |
| 14 | 3.0407 | 4.0747 | 4.6604 | 6.5706 | 7.7895 | 21.0641 | 23.6848 | 29.1412 | 31.3193 | 36.1233 |
| 15 | 3.4827 | 4.6009 | 5.2293 | 7.2609 | 8.5468 | 22.3071 | 24.9958 | 30.5779 | 32.8013 | 37.6973 |
| 16 | 3.9416 | 5.1422 | 5.8122 | 7.9616 | 9.3122 | 23.5418 | 26.2962 | 31.9999 | 34.2672 | 39.2524 |
| 17 | 4.4161 | 5.6972 | 6.4078 | 8.6718 | 10.0852 | 24.7690 | 27.5871 | 33.4087 | 35.7185 | 40.7902 |
| 18 | 4.9048 | 6.2648 | 7.0149 | 9.3905 | 10.8649 | 25.9894 | 28.8693 | 34.8053 | 37.1565 | 42.3124 |
| 19 | 5.4068 | 6.8440 | 7.6327 | 10.1170 | 11.6509 | 27.2036 | 30.1435 | 36.1909 | 38.5823 | 43.8202 |
| 20 | 5.9210 | 7.4338 | 8.2604 | 10.8508 | 12.4426 | 28.4120 | 31.4104 | 37.5662 | 39.9968 | 45.3147 |
| 21 | 6.4467 | 8.0337 | 8.8972 | 11.5913 | 13.2396 | 29.6151 | 32.6706 | 38.9322 | 41.4011 | 46.7970 |
| 22 | 6.9830 | 8.6427 | 9.5425 | 12.3380 | 14.0415 | 30.8133 | 33.9244 | 40.2894 | 42.7957 | 48.2679 |
| 23 | 7.5292 | 9.2604 | 10.1957 | 13.0905 | 14.8480 | 32.0069 | 35.1725 | 41.6384 | 44.1813 | 49.7282 |
| 24 | 8.0849 | 9.8862 | 10.8564 | 13.8484 | 15.6587 | 33.1962 | 36.4150 | 42.9798 | 45.5585 | 51.1786 |
| 25 | 8.6493 | 10.5197 | 11.5240 | 14.6114 | 16.4734 | 34.3816 | 37.6525 | 44.3141 | 46.9279 | 52.6197 |