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3 years ago

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Help on math plzzzz....

1 answer:

NARA [144]3 years ago

8 0

5 is c
6 is d
7 is a
Ghfxghxfgdgsfgshsdghfsghfghsfgsgfh

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You are to take a multiple-choice exam consisting of 64 questions with 5 possible responses to each question. Suppose that you h

damaskus [11]

Answer:

a) Expected score on the exam is 12.8.

b) Variance 10.24, Standard deviation 3.2

Step-by-step explanation:

For each question, there are only two possible outcomes. Either you guesses the answer correctly, or you does not. The probability of guessing the answer of a question correctly is independent of other questions. So we use the binomial probability distribution to solve this question.

Binomial probability distribution

Probability of exactly x sucesses on n repeated trials, with p probability.

The expected value of the binomial distribution is:

$E(X) = np$

The variance of the binomial distribution is:

$V(X) = np(1-p)$

The standard deviation of the binomial distribution is:

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

64 questions.

So $n = 64$

5 possible answers, one correctly, chosen at random:

So $p = \frac{1}{5} = 0.2$

(a) What is your expected score on the exam?

$E(X) = np = 64*0.2 = 12.8$

(b) Compute the variance and standard deviation of x. Variance =Standard deviation

$V(X) = np(1-p) = 64*0.2*0.8 = 10.24$

Variance 10.24

$\sqrt{V(X)} = \sqrt{np(1-p)} = \sqrt{64*0.2*0.8} = 3.2$

Standard deviation 3.2

5 0

3 years ago

How do I solve 372 = -3x - 6(8x + 6)? I already know that x = -8, but I need to know the process of how to get it.

ziro4ka [17]

The value of x is -8

Step-by-step explanation:

The steps of solving an equation of one variable

Simplify the two sides of the equation
Separate the variable in one side and the numerical term in the other side
Divide the both sides by the coefficient of the variable

∵ 372 = -3x - 6(8x + 6)

- Simplify the R.H.S. of the equation by multiplying the bracket by 6

∵ 372 = -3x - [6(8x) + 6(6)]

- You must put the square bracket because the sign in-front of 6

is (-) and the (-) changes the signs after it

∴ 372 = -3x - [48x + 36]

- Remember (-)(+) = (-), multiply the square bracket by (-)

∴ 372 = -3x - 48x - 36

- Add the like terms in the R.H.S.

∴ 372 = -51x - 36

- Add 36 to both sides to separate x in the R.H.S.

∴ 408 = -51x

- Divide both sides by -51 (coefficient of x)

∴ -8 = x

I hope these steps help you

The value of x is -8

Learn more:

You can learn more about the equations in brainly.com/question/11306893

#LearnwithBrainly

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