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AP Statistics Binomial Practice Test |
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Disjointed events are mutually
exclusive. |
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If 65% of the voters believe that the president is doing a good job, what is
the probability of selecting a sample of 150 voters in which 55% to 70%
think the president is doing a good job?
binom cdf (150, 0.65, 105) -
binom cdf (150, 0.65, 81) = 91.2% |
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Give a distribution, how would you calculate probabilities ?
Find the area under the distribution. |
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If there is a 60 % chance that a person will be right, what is the
probability of no more than three being wrong in a 5 person group?
binom cdf (5, 0.4, 3) = 91.3% |
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Which of the following are not true about discrete probability
distributions? |
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a) Negative probabilities are not possible |
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b) The probabilities add up to 1. |
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c) The distributions are symmetrical |
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d) The standard deviation can have a value that is greater than the mean |
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e) All the answers are true. |
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Seven people are are seated in a row at the theater. Three have red hair.
How many different ways are there to seat the people with red hair?
nCr = 35 |
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If 70 % of Americans like country music, what is the probability of having
at least five people in a 20 person group who do not like country music?
p = 1 - binomcdf (20, .3, 4) 76.25% |
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Albert rolls a single six sided die multiple times. What is the probability
that he gets a six in less than 12 rolls?
geomet cdf (1/6, 11) = 86.54% |
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Assume the probability that a golfer will shoot par is 0.3 . What is the
probability that he will shoot par for the 1st time on exactly his 4th hole?
geomet pdf (0.3, 4) = .1029 |
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Sally and Juan form a golf team. Sally's standard deviation is 4 while
Juan's is 3. What is the standard deviation of their combined scores?
( 42 + 32)0.5 = 5,
note that variances can be directly added but not standard deviations. |
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Find the mean for a binomial distribution given n = 10, p = 0.8
number = 8 or fraction = 0.8 |
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Find the standard deviation for a binomial distribution given n = 10, p =
0.8 std dev = 1.265 |
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Bob's quiz standard deviation is 2 and Martha's is 3. Find the standard
deviation of their combined quiz results. Assume Bob's score is independent
of Martha's. 3.606 |
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Bob's quiz standard deviation is 2 and Martha's is 3. Find the standard
deviation of the distribution resulting from Bob's quiz score minus Martha's
score on the same quiz. Assume Bob's score is independent of Martha's.
( 22 + 32)0.5 = 3.606
, note that even though the 2 scores are subtracted, the variances are
added. |
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If 10% of all the apples picked by Martha's are bad. What is the
average number of bad apples that would be found in a barrel of 200 apples?
np = 20 |
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What is the standard deviation of bad apples in the above problem?
4.243 |
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What is the probability that there will be no more than 20 bad apples in a
barrel of 200? binom cdf (200, .1, 20) = 55.92% |
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What is the probability that Martha will pull out the first bad apple
within the
first three tries (assume replacement)? geomet cdf (.1, 3) = 27.1% |
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What is the probability that Martha will pull out the first bad apple on the
second try (assume replacement)? geomet pdf (.1, 2) = 9% |
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Describe a geometric distribution?
range is 1 to positive infinity, skewed right, 1 has highest probability |
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What is the key difference between a Geometric and binomial distribution? Binomial:
Finds the
probability that k success will occur in n number of
attempts.
- Geometric: Finds the probability
that a success will occur for the first time on the nth try.
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