# Probability

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```					       Probability of Earning A Proficient Score On A Multiple Choice Test

Demo
Number of test items:     40        40
% correct needed for proficiency:    45%       45%
Number of choices per item:       4        4

Percent of items the student knows the answer to:     20%       25%
Percent of items in which a student must randomly guess:      35%       25%
Percent of items in which a student can eliminate one choice:    20%       25%
Percent of items in which a student can eliminate two choices:    25%       25%
Percent of items in which a student can eliminate three choices:    0%       0%
Percent of items in which a student can eliminate four choices:    0%       0%

Items needed for proficiency:     18        18
P(Correct answer | Guesses):     0.25      0.25
P(Correct answer | Eliminates one choice):    0.33      0.33
P(Correct answer | Eliminates two choices):    0.50      0.50
P(Correct answer | Eliminates three choices):    1.00      1.00
P(Correct answer | Eliminates four choices):    N/A       N/A

Probability of answering any single item correctly:   47.92% 52%
Probability of earning a proficient score: 70.02% 85%
Probability of not earning a proficient score: 29.98% 15%

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 views: 85 posted: 9/15/2009 language: English pages: 1