Fall 2020 MATH 233
Exam 2
Theory of Probability
Wednesday November 11, 2020 2:00pm – 3:15pm
概率论Exam代写 Nationwide, the Math SAT exam has an average score of 500 (out of 800) and a standard deviationof 120 (assuming a normal distribution).
Your answer to each question (or sub-question), should be contiguous as you will have to clearly mark where your answer is when submitting to Gradescope.
- No collaboration allowed.
- Nooutside sources allowed (no notes, no books, etc.).
- Only scientific calculators are allowed.
- Tablesof the standard normal PDF and CDF are included.
- Nocredit will be given without showing ALL work.
- Pleaseplace a box around your answer for each question.
A scanned PDF must be uploaded to Gradescope by 3:25pm. No late submissions will be accepted.
Useful Random Variables 概率论Exam代写
- Binomial(n,p) distribution, k = 0, . . . , n
(1)
- Poisson(λ)distribution, k = 0, . . . , n
(2)
- Gamma(α,λ) distribution, x > 0
(3)
- Standardnormal distribution, −∞ < x < ∞
(4)
- Exponential(λ)distribution, x > 0
(5)
1.Nationwide, the Math SAT exam has an average score of 500 (out of 800) and a standard deviationof 120 (assuming a normal distribution).
概率论Exam代写
(a)[ 5 points ] If five students who took the exam are selected at random, what is the probabilitythat exactly two of them scored at least 680?
(b)[ 5 points ] What is the probability that a randomly chosen senior scored less than400?
2.[ 5 points ] An insurance company insures 3000 people, each of whom will be in an accident with probability 0.001. Approximate the probability that the insurance company will have to payout on at most 2 accidents. 概率论Exam代写
3.[ 5 points ] The median of a random variable X is the value x such that P[X ≤ x] = 0. Compute the median of X ∼Exponential(3).
4.[ 10 points ] The mode of a continuous random variable is the value x which maximizes f (x), where f is the probability density function of . Find the mode of a Gamma(4.5, 0.5) random variable.
5.Considerthe discrete random variable X with probability mass function P[X = n] = C 3−|n|, for n = . . . , −2, −1, 0, 1, 2, . . ..
(a)[ 3 points ] Find C. 概率论Exam代写
(b)[ 3 points ] ComputeE[X ].
(c)[ 4 points ] What is P[X 2 = k] for k= 0, 1, 2, . . .?
- Considerthe discrete random variable X defined by its probability mass function:
P[X = 0] = 0.20, P[X = 2] = 0.10,
P[X = 1] = 0.20, P[X = 3] = 0.50. (6)
(a)[ 5 points ] What is the expected value, µ, of X?
(b)[ 5 points ] What is the variance, σ2, of X?
7.[ 10 points ] Let X ∼ Binomial(123, 0.40). Use the normal approximation to the binomial distribution to estimate P[X= 42]. 概率论Exam代写
8.[ 5 points ] Let Z be a standard normal random variable, with PDF denoted by ϕ and CDF denoted by Φ. Let X = Φ(Z). How is Xdistributed?
9.[ 5 points ] Let the random variable X ∼ Exponential(λ). Compute the probability density function of Y = F (X ), where F is the CDF ofX .
10.Let the random variable Z ∼ N (0,1).
(a)[ 7 points ] Compute the probability density function of Y =Z2.
(b)[ 3 points] What kind of random variable is ? (Hint: Look at the PDFs on the first page of the exam. )
11.Considerthe continuous random variable X with density function f (x) = Cxe−2x for x ≥ 0. 概率论Exam代写
(a)[ 3 points] What is C?
(b)[ 3 points ] Find the distribution function F.
(c)[ 4 points ] What is P[X ≥1]?
12.[ 10 points ] Let X ∼ Exponential(λ), and Y = log X (i.e. the natural logarithm of X ). What isthe probability density function for Y?
Standard normal PDF
Decimal part \ Integer part | 0 | 1 | 2 | 3 | 4 |
0.00 | 0.398942 | 0.241971 | 0.053991 | 0.004432 | 0.000134 |
0.02 | 0.398862 | 0.237132 | 0.051864 | 0.004173 | 0.000124 |
0.04 | 0.398623 | 0.232297 | 0.049800 | 0.003928 | 0.000114 |
0.06 | 0.398225 | 0.227470 | 0.047800 | 0.003695 | 0.000105 |
0.08 | 0.397668 | 0.222653 | 0.045861 | 0.003475 | 0.000097 |
0.10 | 0.396953 | 0.217852 | 0.043984 | 0.003267 | 0.000089 |
0.12 | 0.396080 | 0.213069 | 0.042166 | 0.003070 | 0.000082 |
0.14 | 0.395052 | 0.208308 | 0.040408 | 0.002884 | 0.000076 |
0.16 | 0.393868 | 0.203571 | 0.038707 | 0.002707 | 0.000070 |
0.18 概率论Exam代写 | 0.392531 | 0.198863 | 0.037063 | 0.002541 | 0.000064 |
0.20 | 0.391043 | 0.194186 | 0.035475 | 0.002384 | 0.000059 |
0.22 | 0.389404 | 0.189543 | 0.033941 | 0.002236 | 0.000054 |
0.24 | 0.387617 | 0.184937 | 0.032460 | 0.002096 | 0.000050 |
0.26 | 0.385683 | 0.180371 | 0.031032 | 0.001964 | 0.000046 |
0.28 | 0.383606 | 0.175847 | 0.029655 | 0.001840 | 0.000042 |
0.30 | 0.381388 | 0.171369 | 0.028327 | 0.001723 | 0.000039 |
0.32 | 0.379031 | 0.166937 | 0.027048 | 0.001612 | 0.000035 |
0.34 | 0.376537 | 0.162555 | 0.025817 | 0.001508 | 0.000032 |
0.36 概率论Exam代写 | 0.373911 | 0.158225 | 0.024631 | 0.001411 | 0.000030 |
0.38 | 0.371154 | 0.153948 | 0.023491 | 0.001319 | 0.000027 |
0.40 | 0.368270 | 0.149727 | 0.022395 | 0.001232 | 0.000025 |
0.42 | 0.365263 | 0.145564 | 0.021341 | 0.001151 | 0.000023 |
0.44 | 0.362135 | 0.141460 | 0.020328 | 0.001075 | 0.000021 |
0.46 | 0.358890 | 0.137417 | 0.019356 | 0.001003 | 0.000019 |
0.48 | 0.355533 | 0.133435 | 0.018423 | 0.000936 | 0.000017 |
0.50 | 0.352065 | 0.129518 | 0.017528 | 0.000873 | 0.000016 |
0.52 | 0.348493 | 0.125665 | 0.016670 | 0.000814 | 0.000015 |
0.54 | 0.344818 | 0.121878 | 0.015848 | 0.000758 | 0.000013 |
0.56 | 0.341046 | 0.118157 | 0.015060 | 0.000706 | 0.000012 |
0.58 | 0.337180 | 0.114505 | 0.014305 | 0.000657 | 0.000011 |
0.60 | 0.333225 | 0.110921 | 0.013583 | 0.000612 | 0.000010 |
0.62 | 0.329184 | 0.107406 |
0.012892 |
0.000569 | 0.000009 |
0.64 | 0.325062 | 0.103961 | 0.012232 | 0.000529 | 0.000008 |
0.66 | 0.320864 | 0.100586 | 0.011600 | 0.000492 | 0.000008 |
0.68 概率论Exam代写 | 0.316593 | 0.097282 | 0.010997 | 0.000457 | 0.000007 |
0.70 | 0.312254 | 0.094049 | 0.010421 | 0.000425 | 0.000006 |
0.72 | 0.307851 | 0.090887 | 0.009871 | 0.000394 | 0.000006 |
0.74 | 0.303389 | 0.087796 | 0.009347 | 0.000366 | 0.000005 |
0.76 | 0.298872 | 0.084776 | 0.008846 | 0.000340 | 0.000005 |
0.78 | 0.294305 | 0.081828 | 0.008370 | 0.000315 | 0.000004 |
0.80 | 0.289692 | 0.078950 | 0.007915 | 0.000292 | 0.000004 |
0.82 | 0.285036 | 0.076143 | 0.007483 | 0.000271 | 0.000004 |
0.84 | 0.280344 | 0.073407 | 0.007071 | 0.000251 | 0.000003 |
0.86 概率论Exam代写 | 0.275618 | 0.070740 | 0.006679 | 0.000232 | 0.000003 |
0.88 | 0.270864 | 0.068144 | 0.006307 | 0.000215 | 0.000003 |
0.90 | 0.266085 | 0.065616 | 0.005953 | 0.000199 | 0.000002 |
0.92 | 0.261286 | 0.063157 | 0.005616 | 0.000184 | 0.000002 |
0.94 | 0.256471 | 0.060765 | 0.005296 | 0.000170 | 0.000002 |
0.96 | 0.251644 | 0.058441 | 0.004993 | 0.000157 | 0.000002 |
0.98 | 0.246809 | 0.056183 | 0.004705 | 0.000145 | 0.000002 |
Standard normal CDF
Decimal part \ Integer part | 0 | 1 | 2 | 3 | 4 |
0.00 | 0.500000 | 0.841345 | 0.977250 | 0.998650 | 0.999968 |
0.02 | 0.507978 | 0.846136 | 0.978308 | 0.998736 | 0.999971 |
0.04 | 0.515953 | 0.850830 | 0.979325 | 0.998817 | 0.999973 |
0.06 | 0.523922 | 0.855428 | 0.980301 | 0.998893 | 0.999975 |
0.08 概率论Exam代写 | 0.531881 | 0.859929 | 0.981237 | 0.998965 | 0.999977 |
0.10 | 0.539828 | 0.864334 | 0.982136 | 0.999032 | 0.999979 |
0.12 | 0.547758 | 0.868643 | 0.982997 | 0.999096 | 0.999981 |
0.14 | 0.555670 | 0.872857 | 0.983823 | 0.999155 | 0.999983 |
0.16 | 0.563559 | 0.876976 | 0.984614 | 0.999211 | 0.999984 |
0.18 | 0.571424 | 0.881000 | 0.985371 | 0.999264 | 0.999985 |
0.20 | 0.579260 | 0.884930 | 0.986097 | 0.999313 | 0.999987 |
0.22 | 0.587064 | 0.888768 | 0.986791 | 0.999359 | 0.999988 |
0.24 | 0.594835 |
0.892512 |
0.987455 | 0.999402 | 0.999989 |
0.26 | 0.602568 | 0.896165 | 0.988089 | 0.999443 | 0.999990 |
0.28 | 0.610261 | 0.899727 | 0.988696 | 0.999481 | 0.999991 |
0.30 | 0.617911 | 0.903200 | 0.989276 | 0.999517 | 0.999991 |
0.32 | 0.625516 | 0.906582 | 0.989830 | 0.999550 | 0.999992 |
0.34 | 0.633072 | 0.909877 | 0.990358 | 0.999581 | 0.999993 |
0.36 | 0.640576 | 0.913085 | 0.990863 | 0.999610 | 0.999993 |
0.38 | 0.648027 | 0.916207 | 0.991344 | 0.999638 | 0.999994 |
0.40 | 0.655422 | 0.919243 | 0.991802 | 0.999663 | 0.999995 |
0.42 | 0.662757 | 0.922196 | 0.992240 | 0.999687 | 0.999995 |
0.44 | 0.670031 | 0.925066 | 0.992656 | 0.999709 | 0.999996 |
0.46 | 0.677242 | 0.927855 | 0.993053 | 0.999730 | 0.999996 |
0.48 | 0.684386 | 0.930563 | 0.993431 | 0.999749 | 0.999996 |
0.50 | 0.691462 | 0.933193 | 0.993790 | 0.999767 | 0.999997 |
0.52 | 0.698468 | 0.935745 | 0.994132 | 0.999784 | 0.999997 |
0.54 | 0.705401 | 0.938220 | 0.994457 | 0.999800 | 0.999997 |
0.56 | 0.712260 | 0.940620 | 0.994766 | 0.999815 | 0.999997 |
0.58 | 0.719043 | 0.942947 | 0.995060 | 0.999828 | 0.999998 |
0.60 | 0.725747 | 0.945201 | 0.995339 | 0.999841 | 0.999998 |
0.62 概率论Exam代写 | 0.732371 | 0.947384 | 0.995604 | 0.999853 | 0.999998 |
0.64 | 0.738914 | 0.949497 | 0.995855 | 0.999864 | 0.999998 |
0.66 | 0.745373 | 0.951543 | 0.996093 | 0.999874 | 0.999998 |
0.68 | 0.751748 | 0.953521 | 0.996319 | 0.999883 | 0.999999 |
0.70 | 0.758036 | 0.955435 | 0.996533 | 0.999892 | 0.999999 |
0.72 | 0.764238 | 0.957284 | 0.996736 | 0.999900 | 0.999999 |
0.74 | 0.770350 | 0.959070 | 0.996928 | 0.999908 | 0.999999 |
0.76 | 0.776373 | 0.960796 | 0.997110 | 0.999915 | 0.999999 |
0.78 | 0.782305 | 0.962462 | 0.997282 | 0.999922 | 0.999999 |
0.80 | 0.788145 | 0.964070 | 0.997445 | 0.999928 | 0.999999 |
0.82 | 0.793892 | 0.965620 | 0.997599 | 0.999933 | 0.999999 |
0.84 | 0.799546 | 0.967116 | 0.997744 | 0.999938 | 0.999999 |
0.86 | 0.805105 | 0.968557 | 0.997882 | 0.999943 | 0.999999 |
0.88 | 0.810570 | 0.969946 | 0.998012 | 0.999948 | 0.999999 |
0.90 | 0.815940 | 0.971283 | 0.998134 | 0.999952 | 1.000000 |
0.92 | 0.821214 | 0.972571 | 0.998250 | 0.999956 | 1.000000 |
0.94 | 0.826391 | 0.973810 | 0.998359 | 0.999959 | 1.000000 |
0.96 | 0.831472 | 0.975002 | 0.998462 | 0.999963 | 1.000000 |
0.98 | 0.836457 | 0.976148 | 0.998559 | 0.999966 | 1.000000 |