Top Banner
Quiz 3 Lucy D’Agostino McGowan September 9, 2014 Q1 Rosner’s Ch 5 Nutrition set of problems, 5.6 - 5.9. 5.6 140-124 20 = 16 20 = .8 1-pnorm(.8) ## [1] 0.2119 21.2% 5.7 90-124 20 = -1.7 1-pnorm(1.7) ## [1] 0.04457 4.46% 5.8 140-121 19 =1 1-pnorm(1) ## [1] 0.1587 15.9% 5.9 90-121 19 = -1.63158 1-pnorm(1.63158) ## [1] 0.05138 5.2% Q2 Rosner’s Ch 5 Nutrition set of problems, 5.21 - 5.24. 5.21 2.5-3.5 0.6 = -1 0.6 = -1.667 1
8

Quiz 3 - Vanderbilt Universitybiostat.mc.vanderbilt.edu/.../Bios311Syllabus2014/Quiz_3.pdf · Quiz 3 Author: Lucy D'Agostino McGowan Created Date: 9/10/2014 7:44:54 PM ...

Mar 17, 2020

Download

Documents

dariahiddleston
Welcome message from author
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
  • Quiz 3Lucy D’Agostino McGowan

    September 9, 2014

    Q1 Rosner’s Ch 5 Nutrition set of problems, 5.6 - 5.9.

    5.6140−124

    20 =1620 = .8

    1-pnorm(.8)

    ## [1] 0.2119

    21.2%

    5.790−124

    20 = −1.7

    1-pnorm(1.7)

    ## [1] 0.04457

    4.46%

    5.8140−121

    19 = 1

    1-pnorm(1)

    ## [1] 0.1587

    15.9%

    5.990−121

    19 = −1.63158

    1-pnorm(1.63158)

    ## [1] 0.05138

    5.2%

    Q2 Rosner’s Ch 5 Nutrition set of problems, 5.21 - 5.24.

    5.212.5−3.5

    0.6 =−10.6 = -1.667

    1

  • pnorm(-1.66667)

    ## [1] 0.04779

    #orpnorm(2.5,3.5,0.6)

    ## [1] 0.04779

    5.222.5−4

    0.5 =−1.50.5 = -3

    pnorm(-3)

    ## [1] 0.00135

    #orpnorm(2.5,4,0.5)

    ## [1] 0.00135

    5.232.5−(4−0.03∗(30))

    0.02∗30 =2.5−3.1

    0.6 = -1

    pnorm(-1)

    ## [1] 0.1587

    #orpnorm(2.5,4-0.03*30,0.02*30)

    ## [1] 0.1587

    5.245.232.5−(4−0.03∗(50))

    0.02∗50 =2.5−2.5

    0.6 = 0

    pnorm(0)

    ## [1] 0.5

    #orpnorm(2.5,4-0.03*50,0.02*50)

    ## [1] 0.5

    Q3a Let X ~ Binom(20, 0.17). Let Y ~ N( mu=E[X], sigma=sqrt(V[X]) ), i.e. Y is Normal with mean andvariance equal to that of the Binomial X. Take a large sample from each of X and Y and sort them fromsmallest to largest. Plot Y by X. By large, I mean try getting samples of 10ˆ6. If that crashes your laptop,go with 10ˆ5.

    2

  • x

  • sum(y > q3b1)/10^6

    ## [1] 0.1587

    • P( X > E[X] + 2*sqrt(V[X]) )

    sum(x > q3b2)/10^6

    ## [1] 0.04073

    • P( Y > E[X] + 2*sqrt(V[X]) )

    sum(y > q3b2)/10^6

    ## [1] 0.02286

    • P( X > E[X] + 2.5*sqrt(V[X]) )

    sum(x > q3b2.5)/10^6

    ## [1] 0.01251

    • P( Y > E[X] + 2.5*sqrt(V[X]) )

    sum(y > q3b2.5)/10^6

    ## [1] 0.006184

    • P( X > E[X] + 3*sqrt(V[X]) )

    sum(x > q3b3)/10^6

    ## [1] 0.003214

    • P( Y > E[X] + 3*sqrt(V[X]) )

    sum(y > q3b3)/10^6

    ## [1] 0.001302

    Q4a Repeat Q3a for Binom(100, 0.17).

    x

  • 5 10 15 20 25 30 35

    010

    2030

    x

    y

    Q4b Repeat Q3b for Binom(100, 0.17).

    q3b1 q3b1)/10^6

    ## [1] 0.1587

    • P( X > E[X] + 2*sqrt(V[X]) )

    sum(x > q3b2)/10^6

    5

  • ## [1] 0.02712

    • P( Y > E[X] + 2*sqrt(V[X]) )

    sum(y > q3b2)/10^6

    ## [1] 0.02262

    • P( X > E[X] + 2.5*sqrt(V[X]) )

    sum(x > q3b2.5)/10^6

    ## [1] 0.008045

    • P( Y > E[X] + 2.5*sqrt(V[X]) )

    sum(y > q3b2.5)/10^6

    ## [1] 0.006088

    • P( X > E[X] + 3*sqrt(V[X]) )

    sum(x > q3b3)/10^6

    ## [1] 0.00205

    • P( Y > E[X] + 3*sqrt(V[X]) )

    sum(y > q3b3)/10^6

    ## [1] 0.001265

    Q5a Repeat Q3a for Binom(1000, 0.17).

    x

  • 120 140 160 180 200 220

    120

    160

    200

    x

    y

    Q5b Repeat Q3b for Binom(1000, 0.17).

    q3b1 q3b1)/10^6

    ## [1] 0.1586

    • P( X > E[X] + 2*sqrt(V[X]) )

    sum(x > q3b2)/10^6

    7

  • ## [1] 0.02538

    • P( Y > E[X] + 2*sqrt(V[X]) )

    sum(y > q3b2)/10^6

    ## [1] 0.02263

    • P( X > E[X] + 2.5*sqrt(V[X]) )

    sum(x > q3b2.5)/10^6

    ## [1] 0.007375

    • P( Y > E[X] + 2.5*sqrt(V[X]) )

    sum(y > q3b2.5)/10^6

    ## [1] 0.006216

    • P( X > E[X] + 3*sqrt(V[X]) )

    sum(x > q3b3)/10^6

    ## [1] 0.001711

    • P( Y > E[X] + 3*sqrt(V[X]) )

    sum(y > q3b3)/10^6

    ## [1] 0.00131

    Q6 Discuss what Q3 - Q5 teaches us. A bullet point discussion is fine.As we increase the number of trials, we see that the binomial distribution better approximates the normaldistribution

    8