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MaRussiya [10]
2 years ago
7

The expected value of a random variable, x, is also called the mean of the distribution of that random variable. Why

Mathematics
1 answer:
egoroff_w [7]2 years ago
3 0

Answer:

See explanation below.

Step-by-step explanation:

If our random variable X is discrete the expected value is given by:

E(X) = \mu = \sum_{i=1}^n X_i P(X_i)

Where X_i represent the possible values for the random variable and P the respective probabilities, so then is like a  weighted average. The only difference is that the mean is defined as:

\bar X = \frac{\sum_{i=1}^n X_i}{n}

On this mean the weight for each observation is \frac{1}{n} and for the expected value are different. But the formulas are equivalent.

If our random variable is continuous then the expected value is given by:

E(X) =\mu = \int_{a}^b f(x) dx

Where f(x) represent the density function for the random variable and a is the lower limit and b the upper limit where the random variable is defined.

And again is analogous to the mean since we are finding the area below the curve of a function.

We assume that is called mean because is a measure of central tendency in order to see where we have the first moment of a random variable. And since takes in count all the weigths for the possible values for the random variable makes sense called mean.

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Which questions best describes: A tire manufacturer has a 60,000 mile warranty for tread life. The manufacturer considers the ov
seropon [69]

This question is incomplete because the answer choices were not provided. The complete question was obtained from google as:

A tire manufacturer has a 60,000 mile warranty for tread life. The manufacturer considers the overall tire quality to be acceptable if less than 5% are worn out at 60,000 miles. The manufacturer tests 250 tires that have been used for 60,000 miles. They find that 3.6% of them are worn out. With this data, we test the following hypotheses.

H0: The proportion of tires that are worn out after 60,000 miles is equal to 0.05.

Ha: The proportion of tires that are worn out after 60,000 miles is less than 0.05.

In order to assess the evidence, which question best describes what we need to determine?

a. If we examine a sample of tires used for 60,000 miles and determine the proportion that are worn out, how likely is that proportion to be 3.6% or less?

b. If we examine the proportion of worn out tires in the population of tires used for 60,000 miles, how likely is that proportion to be 5%?

c. If we examine the proportion of worn out tires in the population of tires used for 60,000 miles, how likely is that proportion to be less than 5%?

d. If we examine the proportion of worn out tires in the population of tires used for 60,000 miles, how likely is that proportion to be 3.6%?

e. If we examine a sample of tires used for 60,000 miles and determine the proportion that are worn out, how likely is that proportion to be less than 5%?

Answer:

Option A is the correct question - If we examine a sample of tires used for 60,000 miles and determine the proportion that is worn out, how likely is that proportion to be 3.6% or less?

Step-by-step explanation:

The correct question that describes what needs to be determined is expressed in option A as this will give us p-value and we will guide us in deciding whether to keep or reject the null hypothesis

Thus option A is the correct question - If we examine a sample of tires used for 60,000 miles and determine the proportion that is worn out, how likely is that proportion to be 3.6% or less?

7 0
3 years ago
Yo I need help wit this
BaLLatris [955]

It’s the third option

3 0
2 years ago
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An alrcraft factory manufactures airplane engines. The unit cost C (the cost in dollars to make each airplane engine) depends on
rewona [7]

C(x) should be ;

C(x)=0.9x² - 306x +36,001

Answer:

$9991

Step-by-step explanation:

Given :

C(x)=0.9x^2 - 306x +36,001

To obtain minimum cost :

Cost is minimum when, C'(x) = 0

C'(x) = 2(0.9x) - 306 = 0

C'(x) = 1.8x - 306 = 0

1.8x - 306 = 0

1.8x = 306

x = 306 / 1.8

x = 170

Hence, put x = 170 in C(x)=0.9x²- 306x +36,001 to obtain the

C(170) = 0.9(170^2) - 306(170) + 36001

C(170) = 26010 - 52020 + 36001

= 9991

Minimum unit cost = 9991

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What is 679 rounded to the nearest ten
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680 is the answer to that question
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What is 2+2. Im in highschool and this is hard.
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Answer:

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2+2=4

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