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Alja [10]
3 years ago
15

Which of these random samples represents a representative sample of the number of students in a middle school who walk to school

? a) All students in chess club b) 25 random 8th graders c) 150 random students at lunch d) 5 students in the hallway
Mathematics
1 answer:
Westkost [7]3 years ago
4 0

Answer:

c

Step-by-step explanation:

150 is a good sample of a middle school and students at lunch is random again because most students eat lunch

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Critical Thinking: Empirical/Quantitative Skills
aliya0001 [1]

Answer:

1. 0.0910 = 9.10% probability that exactly 180 passengers show up for the flight.

2. 0.4522 = 45.22% probability that at most 180 passengers show up for the flight.

3. 0.5478 = 54.78% probability that more than 180 passengers show up for the flight.

Step-by-step explanation:

Binomial probability distribution

The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.

P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}

In which C_{n,x} is the number of different combinations of x objects from a set of n elements, given by the following formula.

C_{n,x} = \frac{n!}{x!(n-x)!}

And p is the probability of X happening.

Can be approximated to a normal distribution, using the expected value and the standard deviation.

The expected value of the binomial distribution is:

E(X) = np

The standard deviation of the binomial distribution is:

\sqrt{V(X)} = \sqrt{np(1-p)}

Normal probability distribution

Problems of normally distributed distributions can be solved using the z-score formula.

In a set with mean \mu and standard deviation \sigma, the zscore of a measure X is given by:

Z = \frac{X - \mu}{\sigma}

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

When we are approximating a binomial distribution to a normal one, we have that \mu = E(X), \sigma = \sqrt{V(X)}.

Assume that there is a 0.905 probability that a passenger with a ticket will show up for the  flight.

This means that p = 0.905

Also assume that the airline sells 200 tickets

This means that n = 200

Question 1:

Exactly, so we can use the P(X = x) formula, to find P(X = 180).

P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}

P(X = 180) = C_{200,180}.(0.905)^{180}.(0.095)^{20} = 0.0910

0.0910 = 9.10% probability that exactly 180 passengers show up for the flight.

2. When 200 tickets are sold, calculate the probability that at most 180 passengers show up for the flight.

Now we have to use the approximation.

Mean and standard deviation:

\mu = E(X) = np = 200*0.905 = 181

\sigma = \sqrt{V(X)} = \sqrt{np(1-p)} = \sqrt{200*0.905*0.095} = 4.15

Using continuity correction, this is P(X \leq 180 + 0.5) = P(X \leq 180.5), which is the p-value of Z when X = 180.5. Thus

Z = \frac{X - \mu}{\sigma}

Z = \frac{180.5 - 181}{4.15}

Z = -0.12

Z = -0.12 has a p-value of 0.4522.

0.4522 = 45.22% probability that at most 180 passengers show up for the flight.

3. When 200 tickets are sold, calculate the probability that more than 180 passengers show up for the flight.

Complementary event with at most 180 passengers showing up, which means that the sum of these probabilities is 1. So

p + 0.4522 = 1

p = 1 - 0.4522 = 0.5478

0.5478 = 54.78% probability that more than 180 passengers show up for the flight.

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My best guess would be A
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A dentist office gives a survey to all wisdom teeth extraction patients asking them to rate the quality of their dental experien
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The correct answer is B. Most patients who have a poor dental experience also have post-extraction complications. This can be shown through the fact that of everyone who had a poor dental experience, 94% said they had post-extraction complication. 94% is obviously <em>most</em>. We can not confidently say that poor dental experiences cause post-extraction problems because we do not know how many people who had a normal or good experience also had problems.
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Find the definding set of the function: y= √(1 - Cos3x ) / (1 + Sin4x )
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y = \frac{\sqrt{\left( 1 - \cos (x\,\text{Rationalize}(0.0523599))\right) }}{\sqrt{\left( 1+\sin (x\,\text{Rationalize}(0.0698132))\right) }}

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Integrated mathematics 2. need help with chapter 5 test please​
Pani-rosa [81]

Answer:

1/4

Step-by-step explanation:

\text{Diamonds, spades, clubs and hearts make up the 4 suits of a deck of cards, }

\text{which contains 52 cards. There are 13 diamonds in a pack.}

\text{Probability of an event:}

\text{ Number of favorable outcomes / Total number of outcomes}

\text{Probability of getting a diamon}d = \frac{13}{52} = \frac{1}{4}.

\text{So the chance that you draw out a diamond from a deck}=\frac{1}{4} .

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