In class A, 17 students in a class of 25 passed an exam. In class B, 13 out of 20 passed. In class C, 7 out of 10 passed. Which
1 answer:
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Answer:
a) probability that the sample will have between 50% and 60% of the identification correct = 0.498
b) The probability is 90% that the sample percentage is contained 45.5% and 54.5% of the population percentage
c) Probability that the sample percentage of correct identifications is greater than 65% = 0.01
Step-by-step explanation:
Sample size, n = 200
Since the brands are equally likely, p = 0.5, q = 0.5
The Standard deviation,
a) probability that the sample will have between 50% and 60% of the identification correct.
Probability that the sample will have between 50% and 60% of the identification correct is 0.498
b) p = 90% = 0.9
Getting the z value using excel:
z = (=NORMSINV(0.9) )
z = 1.281552 = 1.28 ( 2 dp)
Then we can calculate the symmetric limits of the population percentage as follows:
The probability is 90% that the sample percentage is contained 45.5% and 54.5% of the population percentage
c) Probability that the sample percentage of correct identifications is greater than 65%
P(X>0.65) = 1 - P(X<0.65)