probability and statistics

profileJoss_Smitx01
chap003.ppt

McGraw-Hill/Irwin

Copyright © 2008 by The McGraw-Hill Companies, Inc. All rights reserved.

Chapter 3

Probability and Statistics

A Foundation for Becoming a More Effective and Efficient Problem Solver

3-*

Normal Distribution

  • Common probability distribution
  • e.g., height, weight, age, sum of two dice rolled 1,000 times, etc.

3-*

Normal Distribution

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Sheet: Sheet16

0.0

0.1

0.2

0.30000000000000004

0.4

0.5

0.6

0.7

0.7999999999999999

0.8999999999999999

0.9999999999999999

1.0999999999999999

1.2

1.3

1.4000000000000001

1.5000000000000002

1.6000000000000003

1.7000000000000004

1.8000000000000005

1.9000000000000006

2.0000000000000004

2.1000000000000005

2.2000000000000006

2.3000000000000007

2.400000000000001

2.500000000000001

2.600000000000001

2.700000000000001

2.800000000000001

2.9000000000000012

3.0000000000000013

3.1000000000000014

3.2000000000000015

3.3000000000000016

3.4000000000000017

3.5000000000000018

3.600000000000002

3.700000000000002

3.800000000000002

3.900000000000002

4.000000000000002

4.100000000000001

4.200000000000001

4.300000000000001

4.4

4.5

4.6

4.699999999999999

4.799999999999999

4.899999999999999

4.999999999999998

5.099999999999998

5.1999999999999975

5.299999999999997

5.399999999999997

5.4999999999999964

5.599999999999996

5.699999999999996

5.799999999999995

5.899999999999995

5.999999999999995

6.099999999999994

6.199999999999994

6.299999999999994

6.399999999999993

6.499999999999993

6.5999999999999925

6.699999999999992

6.799999999999992

6.8999999999999915

6.999999999999991

7.099999999999991

7.19999999999999

7.29999999999999

7.39999999999999

7.499999999999989

7.599999999999989

7.699999999999989

7.799999999999988

7.899999999999988

7.999999999999988

1.3383022576488534E-4

1.986554713927727E-4

2.919469257914602E-4

4.247802705507514E-4

6.119019301137718E-4

8.726826950457599E-4

0.0012322191684730197

0.001722568939053681

0.00238408820146484

0.0032668190561999178

0.0044318484119380075

0.005952532419775848

0.007915451582979967

0.01042093481442259

0.013582969233685632

0.017528300493568537

0.022394530294842927

0.028327037741601183

0.03547459284623148

0.043983595980427226

0.0539909665131881

0.06561581477467664

0.07895015830089423

0.09404907737688703

0.11092083467945568

0.1295175956658919

0.14972746563574504

0.17136859204780758

0.19418605498321317

0.21785217703255083

0.2419707245191437

0.26608524989875515

0.28969155276148306

0.3122539333667616

0.33322460289179995

0.3520653267642998

0.36827014030332356

0.3813878154605243

0.391042693975456

0.3969525474770118

0.39894228040143265

0.3969525474770117

0.39104269397545577

0.38138781546052397

0.3682701403033232

0.35206532676429947

0.33322460289179967

0.3122539333667614

0.28969155276148295

0.26608524989875515

0.24197072451914378

0.21785217703255105

0.1941860549832135

0.17136859204780797

0.14972746563574552

0.1295175956658924

0.11092083467945624

0.0940490773768876

0.07895015830089482

0.0656158147746772

0.053990966513188625

0.04398359598042771

0.0354745928462319

0.02832703774160159

0.022394530294843257

0.01752830049356885

0.013582969233685878

0.010420934814422817

0.007915451582980144

0.005952532419776001

0.004431848411938125

0.003266819056200014

0.0023840882014649163

0.0017225689390537363

0.0012322191684730624

8.726826950457925E-4

6.119019301137963E-4

4.247802705507695E-4

2.9194692579147323E-4

1.9865547139278204E-4

1.3383022576489198E-4

0.0

1.3383022576488534E-4

0.1

1.986554713927727E-4

0.2

2.919469257914602E-4

0.30000000000000004

4.247802705507514E-4

0.4

6.119019301137718E-4

0.5

8.726826950457599E-4

0.6

0.0012322191684730197

0.7

0.001722568939053681

0.7999999999999999

0.00238408820146484

0.8999999999999999

0.0032668190561999178

0.9999999999999999

0.0044318484119380075

1.0999999999999999

0.005952532419775848

1.2

0.007915451582979967

1.3

0.01042093481442259

1.4000000000000001

0.013582969233685632

1.5000000000000002

0.017528300493568537

1.6000000000000003

0.022394530294842927

1.7000000000000004

0.028327037741601183

1.8000000000000005

0.03547459284623148

1.9000000000000006

0.043983595980427226

2.0000000000000004

0.0539909665131881

2.1000000000000005

0.06561581477467664

2.2000000000000006

0.07895015830089423

2.3000000000000007

0.09404907737688703

2.400000000000001

0.11092083467945568

2.500000000000001

0.1295175956658919

2.600000000000001

0.14972746563574504

2.700000000000001

0.17136859204780758

2.800000000000001

0.19418605498321317

2.9000000000000012

0.21785217703255083

3.0000000000000013

0.2419707245191437

3.1000000000000014

0.26608524989875515

3.2000000000000015

0.28969155276148306

3.3000000000000016

0.3122539333667616

3.4000000000000017

0.33322460289179995

3.5000000000000018

0.3520653267642998

3.600000000000002

0.36827014030332356

3.700000000000002

0.3813878154605243

3.800000000000002

0.391042693975456

3.900000000000002

0.3969525474770118

4.000000000000002

0.39894228040143265

4.100000000000001

0.3969525474770117

4.200000000000001

0.39104269397545577

4.300000000000001

0.38138781546052397

4.4

0.3682701403033232

4.5

0.35206532676429947

4.6

0.33322460289179967

4.699999999999999

0.3122539333667614

4.799999999999999

0.28969155276148295

4.899999999999999

0.26608524989875515

4.999999999999998

0.24197072451914378

5.099999999999998

0.21785217703255105

5.1999999999999975

0.1941860549832135

5.299999999999997

0.17136859204780797

5.399999999999997

0.14972746563574552

5.4999999999999964

0.1295175956658924

5.599999999999996

0.11092083467945624

5.699999999999996

0.0940490773768876

5.799999999999995

0.07895015830089482

5.899999999999995

0.0656158147746772

5.999999999999995

0.053990966513188625

6.099999999999994

0.04398359598042771

6.199999999999994

0.0354745928462319

6.299999999999994

0.02832703774160159

6.399999999999993

0.022394530294843257

6.499999999999993

0.01752830049356885

6.5999999999999925

0.013582969233685878

6.699999999999992

0.010420934814422817

6.799999999999992

0.007915451582980144

6.8999999999999915

0.005952532419776001

6.999999999999991

0.004431848411938125

7.099999999999991

0.003266819056200014

7.19999999999999

0.0023840882014649163

7.29999999999999

0.0017225689390537363

7.39999999999999

0.0012322191684730624

7.499999999999989

8.726826950457925E-4

7.599999999999989

6.119019301137963E-4

7.699999999999989

4.247802705507695E-4

7.799999999999988

2.9194692579147323E-4

7.899999999999988

1.9865547139278204E-4

7.999999999999988

1.3383022576489198E-4

3-*

Mean and Standard Deviation

  • Most common statistics used
  • Mean or expected value

E(x) = SxiP(xi)

  • Standard deviation

s(x) = [S [xi - E(x)]2P(xi)]0.5

s(x) = [S [xi - m]2/n-1]0.5

3-*

Z-Scores

  • Standard Z-score
  • Measures the number of standard deviations away from the mean
  • Calculated as such:

  • Look up Z value in table to find probability

Normal Distribution

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0

1

2

3

4

5

6

7

8

x

P(x)

Normal Distribution

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0

1

2

3

4

5

6

7

8

x

P(x)

mean = 4, std. dev. = 1

-1 std. dev.

+1 std. dev.

68% of values

m

=

x

i

å

n

Z

=

x

-

mean

SD