A biology quiz consists of 14 multiple-choice questions. Nine must be answered correctly to receive a passing grade. If each question has 4 possible answers,what is the probability that a student who guesses at random will pass?

Answer 1
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Answer 2

#0.002154#

#C(14,9) (1/4)^9 (3/4)^5 + C(14,10) (1/4)^10 (3/4)^4 + C(14,11) (1/4)^11 (3/4)^3 + C(14,12) (1/4)^12 (3/4)^2 + C(14,13) (1/4)^13 (3/4) + (1/4)^14 = 0.001812 + 0.000302 + 0.000037 + 0.000003 + 0.000000 + 0.000000 = 0.002154#

#C(n,k) = (n!) / ((n-k)!k!)#
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Answer 3

#0.0022#

This is Binomial with #n= 14, p= 1/4 = 0.25# and you need to find this probability:
#P(X >= 9)# = Sum from #x=9# to #x = 14: 14Cx (0.25^x)(0.75)^(14-x)#

If you some all 6 terms of this Binomial you will get the answer:

#P(X >= 9) = 0.0022#
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Answer 4

To calculate the probability that a student who guesses at random will pass the biology quiz:

  1. Determine the probability of guessing a single question correctly. Since each question has 4 possible answers and only one is correct, the probability of guessing correctly is ( \frac{1}{4} ).
  2. Use the binomial probability formula to calculate the probability of getting at least 9 questions correct out of 14 attempts.
  3. Calculate the probability of passing by summing up the probabilities of getting 9, 10, 11, 12, 13, or 14 questions correct.
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Answer from HIX Tutor

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.

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