Presnell dwackerly lecture 7 sta 2023 c bpresnell

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: ¥¤&© § £ § 5 £¢ ©§# 4 £ %1#¢ £ %6#¤¦¥¤&F%$"¦¥¤¢ §#! £ %$"¦¥¤¢ %6#¤¦¥¤¢ † 2r"(¥'¢ §5 £ §#4 £ ` H ©§ £ ©§ £  %1#¤¢  ¦¥¤¢ Find are ¡ ¥ independent events: and # EXAMPLE : Like #3.52(a), p. 136 Independent (p. 131, 133): `WW`H H ©c ©  ) © 84 STA 2023 c B.Presnell & D.Wackerly - Lecture 7 STA 2023 c B.Presnell & D.Wackerly - Lecture 7 EXAMPLE : (Like # 3.109, p. 158) : HIV test. § EXAMPLE : Space shuttle Challenger disaster. The Rogers commission concluded disaster results unless : person HAS HIV : person does not have HIV @ Suppose we know that F§  6P5  § '¢ © £ ¡ §£ © Q 5P § ¤¢ If (1996 CDC) 476,999/242,200,000 = .00197 is the fraction of pop. that has HIV, then for person selected at random § v  tYUEFQ1P¤¢ U ©§ £ all six work 3 , so “specificity of test” at least 1 fails , , only F. STA 2023 c B.Presnell & D.Wackerly - Lecture 7 Note that § § £ £ §£ Q6P5 § '¢ § b1P¤¢ Q1P'¢ ¡ ¡  VUE§  6P5 § ¤¢ © £ © E§ b6P5  § ¤¢ £ ¡ ¥ FQ65 '¢  © § P §£ § '¢ £ £ § E1P¤¢ F§ § 5 1P¤¢ 4§ £ © ¡ : (WHY?) ¡ ¡ `  tVUE© U § U£ § £ tv  XVU £ e¥  p© § £ £§ £¢ © 4 £ Q1P'¢ ¤Q6P5 § '&§ § 1P'¢ ¡ Since are mutually exclusive § § 5 1P¤¢ £  X VUE©  `  tVUE© U `  tVUE© U `  tVUE© U 4 £¢© £ E1P¤&F§ § ¤¢ § b6P5  § ¤¢ £ Know Thus and How about KNEW ? § § 5 1P¤¢ £ §£ Q6P5 § '¢  HXW G ¨  ` t tYUYU © U § ¤¢ £ £ § E1P¤¢ F§ § 5 1P¤¢ 4§ £ © . £ , and £ , 4 P Want , § £ (cond.) prob. that the person actually has HIV ? Know ? § ¡ A person is selected and tests positive. What is the How about 87 4 § 3QP § § 4 b1P£ !0§ § 41P£p© £ § § § ¤¢ 86 STA 2023 c B.Presnell & D.Wackerly - Lecture 7 P -th of what it was at about ¥ tV‚) U U ¡ `U tX¥  4 VU‚) £  ¡ §  7£'¢ £ §  6P5 § '") P £¢ § § 4  1P¤") § § £¢ at least 1 fails  bP Note: At ` U B © £ tX¥ ¡ E§  1P¤¢ 8 ©(D &¦ `  VUE© e¡W ¡  9§  §¥ £   © £ ¤¢ 3 ¡W EF§ ( 7¤&f¥¤£§ 7¤¢ tW ¥  © D £ ( ¢ © ¡¢ ¢ ¢ © & D £ ¡ U ¡ ` RE¨e¦¥qpF§  ©v  © £ ¤¢ 3 © v  §v £ © e¦¥E© ttv  p§ £ '¢ ( v  © £ ¢ © ¢ ¢¢ © D£ tv E§ ( D 'if¥¤£§ & 7¤¢ ¡` § ( 7¤…§ 7'‡§ 1 7'…§  7¤…§  7'…§ & 7'&© D£ ¢ D£ ¢ D£ ¢ D£ ¢ D£ ¢ D£ ¢ § ( D 4 D 4 1 D 4  $4  $4 & D '&§ DD £¢© £ ¤¢ F), estimate “sensitivity of test” ¥ 8 ©& D all six work Under Challenger flight conditions ( person tests negative P @ Assuming joint failures indep.: : P sixth field joint works person tests positive § . . . :  all six field joints (sealed by O-rings) work. first field joint works 85 , found . £...
View Full Document

This note was uploaded on 12/15/2011 for the course STA 2023 taught by Professor Ripol during the Spring '08 term at University of Florida.

Ask a homework question - tutors are online