please solve this question within 20 Min
2. (简答题, 30.0分) Let X denote a random variable that takes on any of the values -1, 0, and 1 with respective probabilities P{X = -1}=0.2, P{X = 0} = 0.5, P{X = 1}=0.3. Find the expectation of X

Answer:

There are 47 dimes and 2 pennies.

Step-by-step explanation:

10¢ = 1 dime

$4.70 = 470 ¢

470 dimes = 47 dimes

and 2 pennies

Each side of cube is 100 cm.

In Maths or in Geometry, a Cube is a solid three-dimensional figure, which has 6 square faces, 8 vertices and 12 edges. It is also said to be a regular hexahedron.

Given that,

Volume of cube = 1 cubic meter

We know that,

1 m = 100 cm

Also  volume of cube = \(a^{3}\)

Then,

Volume of cube = 1000000 cm

                   \(a^{3}\)  = \(100^{3}\)

                   a = 100 cm

Hence, Each side of cube is 100 cm.

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Answer:

2080

Step-by-step explanation:

that's the answer i think Good luck :)

Answer:

$3.80, Three dollars and eighty cents

Step-by-step explanation:

:) yw

Answer:

$3.25

Step-by-step explanation:

There are 3 dollar bills, 1 dime (worth 10 cents), and 3 nickles (worth 5 cents each). Just add it all together; and therefore, the value of the money shown is $3.25

Hope this helps :)

The value of α = 0.26 finding by using normal distribution.

A normal distribution is an arrangement of a data set in which most values cluster in the middle of the range and the rest taper off symmetrically toward either extreme.

Given that,

confidence level = 74%

alpha = ?

The significance level α is the probability of making the wrong decision when the null hypothesis is true. Alpha levels which is also called as significance levels are used in hypothesis tests.

Mathematically, the value of α is determined by subtracting the level of confidence from 1, and then writing the result as a decimal.

As the confidence level is given as 74%, so the significance level would be,

α  = 1 - confidence level

 =  1 - 0.74

α = 0.26

Hence, The value of α = 0.26.

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Answer:

Dimension => 10 m × 9.6 m

Step-by-step explanation:

From the question given above, the following data were obtained:

Area (A) = 96 m²

Circumference (C) = 39.2 m

Dimension =.?

Next, we shall determine the Lenght and breadth of the rectangle. This can be obtained as follow:

Let L be the Lenght

Let B be the breadth

Area of a rectangle = L × B

96 = L × B ..... (1)

Circumference of rectangle = 2(L + B)

39.2 = 2(L + B) .... (2)

From equation 2, make L the subject

39.2 = 2(L + B)

Divide both side by 2

39.2 /2 = L + B

19.6 = L + B

Rearrange

L = 19.6 – B ....(3)

Substitute the value of L in equation 3 into equation 1

96 = L × B

L = 19.6 – B

96 = (19.6 – B ) × B

Clear bracket

96 = 19.6B – B²

Rearrange

B² – 19.6B + 96 = 0

Solving by factorisation

B² – 10B – 9.6B + 96 = 0

B(B – 10) – 9.6(B – 10) = 0

(B – 9.6)(B – 10) = 0

B – 9.6 = 0 or B – 10 = 0

B = 9.6 or B = 10

Substitute the value of B into equation 3:

L = 19.6 – B

B = 9.6

L = 19.6 – 9.6

L = 10

Or

L = 19.6 – B

B = 10

L = 19.6 – 10

L = 9.6

Since the length is always longer than the breadth,

Length (L) = 10 m

Breadth (B) = 9.6 m

Finally, we shall determine the dimension of the rectangle. This can be obtained as follow:

Length (L) = 10 m

Breadth (B) = 9.6 m

Dimension =?

Dimension = L × B

Dimension = 10 m × 9.6 m

To conclude that the proportion of those who think that newspapers are boring is different for teenage girls and boys there is not enough evidence.

We are given that;

Number of girls in sample=2050

Number of boys in sample=2600

Now,

We can calculate the test statistic as follows:

\(z = (p_1 - p_2) / \sqrt{(p * (1 - p) * (1/n1 + 1/n2))}\)

where \(x_1\) and \(x_2\)  are the number of girls and boys who think that newspapers are boring, respectively, 2050 and 2600.

Assuming a significance level of 0.05, we can find the critical value(s) from the standard normal distribution. For a two-tailed test, the critical values are -1.96 and 1.96.

If the absolute value of the test statistic is greater than or equal to 1.96, we reject the null hypothesis.

If we have \(x_1\)= 820 and \(x_2\) = 1040, then \(p_1\) = 820/2050 = 0.4 and \(p_2\) = 1040/2600 = 0.4.

Using these values, we can calculate:

p = (820 + 1040) / (2050 + 2600) = 0.4

z = (0.4 - 0.4) / √(0.4 * (1 - 0.4) * (1/2050 + 1/2600)) = 0

Since the absolute value of the test statistic is less than 1.96, we fail to reject the null hypothesis.

Therefore, the sample answer will be there is not enough evidence.

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Answer:

x = 25 and <A = 148 degrees

Step-by-step explanation:

Basically it's asking you to find the value of x for both of those equations, x must be the same for both

6x - 2 = 4x + 48

Answer:

D) \(1 < x\leq 4\)

Step-by-step explanation:

1 is not included, but 4 is included, so we can say \(1 < x\leq 4\)

Answer:

Probability (Fraction, Decimal, Percentage)  = 1/8 , 0.125 , 12.5%

Step-by-step explanation:

Total cards = 8 ; numbered 'three, four, five, six, seven, eight, nine, ten'

Prob (Card with number three) = card with no. three / total cards = 1/8

Prob (Card with number four) = card with no. four / total cards = 1/8

Similarly , Prob (A Card with any other number) = 1/8

Fraction Probability = 1/8 ; Decimal Probability = 0.125

Percentage probability = 1/8 x 100 = 12.5%

The probability that the mean of a month's reviews will take Yoonie from 3.5 to 4.25 hours is 0.7492.

The random variable X is defined as the time it takes her to complete one review.

The random variable X follows a Normal distribution with parameters μ = 4 hours and σ = 1.2 hours.

A random sample of n = 16 reviews are selected as a set.

Compute the probability that the mean of a month’s reviews will take Yoonie from 3.5 to 4.25 hours as follows:

P(3.5 < X < 4.25) = P(3.5-4/1.2√16 < x- μ /σ/√n < 4.25-4/1.2/√16)

=P(-1.67 < Z < 0.83)

= P(Z < 0.83) - (P(Z < -1.67)

= 0.7967 - 0.0475

= 0.7492

Thus, the probability that the mean of a month’s reviews will take Yoonie from 3.5 to 4.25 hours is 0.7492.

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The correct answer is (D) 0.8262

If the z value of the test statistic is equal to 1.36, the corresponding p-value is 0.8262. The p-value represents the probability of obtaining a test statistic as extreme or more extreme than the observed value, assuming the null hypothesis is true.

To determine the p-value, we need to calculate the area under the standard normal curve beyond the observed z value. In this case, the z value is 1.36. By referring to a standard normal distribution table or using a statistical software, we can find the corresponding probability.

Using the standard normal distribution table, we find that the area to the right of 1.36 is approximately 0.0869. However, since the p-value represents the probability of obtaining a value as extreme or more extreme than the observed value, we need to consider both tails of the distribution. Therefore, we multiply the area in one tail by 2, resulting in a p-value of 0.0869 * 2 = 0.1738.

Therefore, the correct answer is 0.8262, as stated in the answer choices.

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Answer: 2.95x+39.95(12)

Step-by-step explanation:

Hi, to answer this question we have t write an expression with the information given:

The yearly cost for x movie rentals is equal to : the product of the cost of each movie (2.95) and the number of movies (x) ;plus the product of the monthly fee (39.95) and the number of months in a year (12)

Mathematically speaking:

2.95x+39.95(12)

Answer:

D-295x+39.95(12)​

Step-by-step explanation:

EDG2021

Answer:

15

Step-by-step explanation:

Answer:

Step-by-step explanation:"To solve this equation, you can start by distributing the 0.20 and 0.30 terms. Then, you can simplify the equation by combining like terms. After that, you can isolate the variable Z on one side of the equation by adding or subtracting terms from both sides. Finally, you can solve for Z. The solution is Z = 1000. Does that help?"

Answer:The statement that incorrectly describes how the graphs of f(x) and g(x) are related is B:The graph of f(x) is shifted 4 units up to create the graph of g(x).

The function f(x) is given as:

f(x) = -34x – 1

The function g(x) is given in terms of f(x) as:

g(x)  =  -4f(x)

Substitute f(x) = -34x - 1 into g(x)

g(x)  =  -4(-34x - 1)

g(x) = 136x  +  4

Find the x-intercept of f(x)

Let f(x) = 0

0 = -34x - 1

x  =  -1/34

The x-intercept of f(x) = (-1/34, 0)

Find the x-intercept of g(x)

Let g(x) = 0

0 = 136x + 4

x  =  -4/136

x  =  -1/34

The x-intercept of g(x) = (-1/34,  0)

It is true that the graph of f(x) has the same x-intercept as the graph of g(x)

The y-intercept of f(x) is -1 and the y-intercept of g(x) = -4

It is true that the y-intercept of f(x) is 5 units below the y-intercept of g(x)

The slope with a greater absolute value is steeper.

The slope of g(x) is greater than that of f(x), therefore, the graph of g(x) is steeper.

The only incorrect statement is option B. The graph of f(x) is shifted 4 units up to create the graph of g(x)

Step-by-step explanation:

From the Venn diagram, the values of a, b, c and d are11,19,35,35 respectively

A Venn diagram is an illustration that uses circles to show the relationships among things or finite groups of things. Circles that overlap have a commonality while Circles that do not overlap do not share those traits.

The universal set is ∈ = 100

The languages are

Spanish = 30

Russian = 54

(S∪ R)¹ = 35 = d

a = Spanish only = a-b

30-b = a

Russia only = c-b

54 - b

Therefore, The universal set ∈ is

100 = (a-b) + (b)+ (c-b) +(d)

100 =  30-b + b + 54 - b + 35

100 = 119 - b = 119-100

b= 19

Therefore,

a = 30 -19 =11

b = 19

c = 59 - 19 35

d = 35

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Answer:

lemon juice : parts sugar

3 :2

? :3

3/2 × 3 = 4,5 cups of lemon

Answer:

4.5

Step-by-step explanation:

the ratio of lemon juice to parts sugar is 3:2.  to convert into cups, it turns into ?:3. to turn 2 into 3, you multiply by 1.5, so you have to do the same to 3, to get 4.5, 3:2 is equal to 4.5:3 so kelly would have to use 4.5 cups of lemon juice.

Answer:

\(2( {3}^{x} ) = 258280326\)

\( {3}^{x} = 129140163\)

\(x = \frac{ ln(129140163) }{ ln(3) } = 17\)

n = 17 + 1 = 18

\(s = \frac{2( 1 - {3}^{18} )}{1 - 3} = 387420488\)

The sum of this finite geometric series is 387,420,488.

The pressure at the depth of 5 meters will be 333.34 N / cm ²

Pressure is defined as the normal force acting at the per unit area of any object.

Given that:-

The pressure at the 5 m below sea level will be:-

3  m  =  200

1  m   =  200 / 3

5 m =  200/3  x   5

5m  =  333.34  N / cm²

Therefore the pressure at the depth of 5 meters will be 333.34 N / cm ²

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There are 20,358,520 different choices for the player in the 6/53 lottery game if repetition is not allowed.

If repetition is not allowed, then the player can choose any of the 53

numbers for the first number, any of the remaining 52 numbers for the

second number, any of the remaining 51 numbers for the third number, and

so on.

Therefore, the number of different choices the player has is:

53 × 52 × 51 × 50 × 49 × 48 = 20,358,520

So there are 20,358,520 different choices for the player in the 6/53 lottery

game if repetition is not allowed.

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O(-, -28] is the formula for resolving the inequality +4 = 0. Inequality is the state of having a connection between two expressions or values that is not equal to them.

A connection between two expressions or values that is not equal in mathematics is referred to as an inequality. Inequality results from an imbalance, thus. In mathematics, an inequality establishes the relationship between two values that are not equal. Egality is not the same as inequality. Use the not equal symbol () in most cases when two values are not equal. To contrast values, whether they are tiny or huge, different inequalities are employed. By adjusting both sides until just the variables are left, you may eliminate many straightforward inequalities. However, several factors cause inequality: Divide or add negative values on both sides. Switch the left and right.

A disparity is presented to us.

\(y+4\leq 0\)

The answer to the inequality must be discovered.

For each side of the inequality, deduct 4

y +4 - 4 ≤ 0 - 4

y ≤ -4

y ∈ ( - ∞ , - 4 ]

As a result, the solution set for the given inequality is provided by y (- , - 4].

O(-, -28] is the formula for resolving the inequality +4 = 0. Inequality is the state of having a connection between two expressions or values that is not equal to them.

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Answer: 1/6, 14/84, 21/126

Step-by-step explanation:

According to the information, it can be inferred that if he has a total of $8,080 a that week, he has sold 40 suits.

To calculate how many suits he sold during that week we must find the total value that he would give with each of the answer options as shown below:

Based on the above, the closest value is $8,000, so we can conclude that he sold 40 suits. Now to find the missing money we must find 10% of 40 and identify the value that these t-shirts would have:

So the total value of all the products would be $8,080.

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Answer: x=26

Step-by-step explanation:

Answer:

f(x)=x²-4x+2

f(-1)= (-1)²-4(-1)+2

= 1+4+2

=7

Answer:

15 kg, 22.5 kg, 52.5 kg

Step-by-step explanation:

Let the common multiplier of the given ratios be x. Therefore, weights of each bag would be 2x, 3x and 7x

According to the given information:

\(2x + 3x + 7x = 90 \\ 12x = 90 \\ x = \frac{90}{12} \\ x = 7.5 \: \\ \implies \\ 2x = 2 \times 7.5 = 15 \: kg \\ 3x = 3 \times 7.5 = 22.5 \: kg \\ 7x = 7 \times 7.5 = 52.5 \: kg\)

Hence the weight of sand in bag would be 15 kg, 22.5 kg and 52.5 kg

Answer:

3 < r

Step-by-step explanation:

167<6+7(2+7r)

distribute the 7 to the 2 and 7r

7 * 2 = 14 and 7 * 7r = 49r

167 < 6 + 14 + 49r

combine like terms: 6 + 14 = 20

167  < 20 + 49r

subtract 20 from both sides

147 < 49r

divide both sides by 49

3 < r

The probability that he will take one patterned and one plain T- shirt is given as follows:

p = 7/18.

The parameters that are needed to calculate a probability are listed as follows:

Then the probability is then calculated as the division of the number of desired outcomes by the number of total outcomes.

The outcomes in this problem are given as follows:

Hence the probability is given as follows:

p = 7/9 x 2/8 + 2/9 x 7/8

p = 28/72

p = 14/36

p = 7/18.

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The probability that exactly 2 employees were over 50 if the dismissed employees were selected at random is 0.2048.

We have to determine the probability that exactly 2 employees were over 50 if the dismissed employees were selected at random. It is given that the town recently dismissed 6 employees to meet their new budget reductions. It is also given that the town had 4 employees over 50 years of age and 17 under 50 years of age. Therefore, total employees in the town = 4 + 17 = 21.

If we assume that all the employees have an equal probability of being selected, then the total number of ways of selecting 6 employees from 21 employees can be given by:21C6 = (21*20*19*18*17*16)/(6*5*4*3*2*1) = 54264Now, the number of ways of selecting exactly 2 employees over 50 from 4 employees over 50 can be given by:4C2 = (4*3)/(2*1) = 6Also, the number of ways of selecting exactly 4 employees under 50 from 17 employees under 50 can be given by:17C4 = (17*16*15*14)/(4*3*2*1) = 2380.

Therefore, the number of ways of selecting 2 employees over 50 and 4 employees under 50 from the total 6 employees can be given by:6C2 * 17C4 = (6*5/2*1) * (17*16*15*14/4*3*2*1) = 3246320.

Hence, the probability that exactly 2 employees were over 50 if the dismissed employees were selected at random is given by:3246320/54264 = 0.2048 (rounded to four decimal places).

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