﻿interval 
  for 
  the 
  estimate 
  that 
  90 
  percent 
  of 
  Alaskan 
  skiers 
  were 
  male 
  would 
  be 
  ±15.80 
  

   percent. 
  The 
  true 
  percentage 
  of 
  the 
  male 
  skiers 
  would 
  probably 
  be 
  between 
  74.2 
  percent 
  

   and 
  100 
  percent. 
  

  

  The 
  confidence 
  percentages 
  for 
  either 
  90 
  percent 
  or 
  10 
  percent, 
  80 
  percent 
  or 
  20 
  

   percent, 
  70 
  percent 
  or 
  30 
  percent, 
  60 
  percent 
  or 
  40 
  percent, 
  and 
  50 
  percent 
  or 
  50 
  per- 
  

   cent, 
  are 
  listed 
  in 
  the 
  same 
  column 
  to 
  save 
  space 
  in 
  this 
  table. 
  In 
  the 
  Alaskan 
  example 
  

   just 
  given, 
  the 
  same 
  confidence 
  interval 
  would 
  apply 
  to 
  an 
  estimate 
  that 
  10 
  percent 
  of 
  

   the 
  Alaskan 
  skiers 
  were 
  male 
  as 
  to 
  the 
  estimate 
  that 
  90 
  percent 
  were 
  male. 
  

  

  The 
  table 
  does 
  not 
  give 
  confidence 
  intervals 
  for 
  percentages 
  other 
  than 
  even 
  10 
  - 
  

   percent 
  increments. 
  However, 
  the 
  reader 
  can 
  interpolate 
  between 
  one 
  column 
  and 
  the 
  

   next. 
  For 
  example, 
  the 
  confidence 
  interval 
  for 
  the 
  estimate 
  that 
  85 
  percent 
  of 
  the 
  

   Alaskan 
  skiers 
  were 
  over 
  30 
  years 
  old 
  would 
  fall 
  approximately 
  halfway 
  between 
  15.80 
  

   and 
  20.26 
  percent, 
  or 
  about 
  18 
  percent. 
  

  

  Table 
  5 
  gives 
  the 
  confidence 
  limits 
  in 
  the 
  same 
  fashion 
  as 
  table 
  3. 
  Table 
  4 
  is 
  to 
  

   be 
  used 
  when 
  the 
  skier 
  population 
  question 
  is 
  limited 
  to 
  skiers 
  19 
  years 
  old 
  and 
  older. 
  

   Thus, 
  table 
  4 
  can 
  be 
  used 
  to 
  determine 
  the 
  confidence 
  limits 
  for 
  skier 
  population 
  esti- 
  

   mates 
  describing 
  the 
  percentage 
  of 
  the 
  skiers 
  in 
  (1) 
  particular 
  income 
  classes, 
  (2) 
  

   proportion 
  of 
  married 
  male 
  or 
  female 
  skiers, 
  and 
  (3) 
  other 
  percentages 
  specifically 
  

   identified 
  as 
  applying 
  only 
  to 
  skiers 
  above 
  the 
  19 
  -year 
  age 
  limit. 
  

  

  57 
  

  

  