Would you consider data on grades (of a particular class)
collected over two semesters to be cross-sectional or times series
data and why?

[tex]sina=\frac{2\sqrt{13} }{13} \\cosa=\frac{3\sqrt{13} }{13}\\tana=\frac{2}{3}[/tex]

Answer:

A.

Step-by-step explanation:

correct on edge2021

The required solutions are:

a) Yes, the relation R is an equivalence relation.

b)The equivalence class of -17 is {-17, -23, -29, -35, ...}.

a) In order to determine whether R is an equivalence relation or not, we need to check if it satisfies the following three conditions:

We can see that the relation 'R' satisfies all the conditions ( reflexibility, symmetry, and transitivity), so R is an equivalence relation.

b) In order to find the equivalence class of -17, we need to find all integers that are related to -17 under the relation R.

We can rewrite the relation as mRn if and only if m' - n' = 6k for some integer k.

In this case, -17Rn if and only if (-17)' - n' = -17 - n = 6k for some integer k.

To find all integers n that satisfy this equation, we can rearrange it as n = -17 - 6k.

By putting in different values of k, we can find all the integers n that are in the equivalence class of -17.

For example, when k = 0, n = -17 - 6(0) = -17. So, -17 is in the equivalence class of -17.

We can also see that when k = 1, n = -17 - 6(1) = -23. So, -23 is also in the equivalence class of -17.

The equivalence class of -17 consists of all integers that can be obtained by subtracting multiples of 6 from -17. So, the equivalence class of -17 is {-17, -23, -29, -35, ...}.

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Answer: You will pay $510 for a item with original price of $600 when discounted 15%.

Set up a ratio of height over shadow for each :

12/8 = 4/x

Cross multiply:

12x = 32

Divide both sides by 12:

X = 2 2/3 feet

The shadow is 2 2/3 feet.

Answer:

For square matrices A and B of equal size, the determinant of a matrix product equals the product of their determinants: det (A.B) = det (A) det (B) 1. A is invertible if and only if its determinant is nonzero 1.

Step-by-step explanation:

Answer:

Variant b

Step-by-step explanation:

If you multiply it should be a+b but if you divided

A+b-c

Q1.1.1 The probability of randomly selecting a male respondent from the sample is 0.4. Q.1.1.2 The probability of randomly selecting a respondent who is female and prefers HP is 0.275. Q.1.1.3 The probability of selecting a male respondent, given that the preferred brand is Lenovo is 0.4545. Q.1.1.4 The probability of selecting a respondent who is male or who prefers HP is 0.575. Q.1.1.5 The probability of selecting a respondent who does not prefer Lenovo is 0.725.

Q.1.1.1 What is the probability of randomly selecting a male respondent from the sample?

The probability of randomly selecting a male respondent is given by the number of male respondents divided by the total number of respondents:

Probability = No. of Males / Total = 160 / 400 = 0.4

Q.1.1.2 What is the probability of randomly selecting a respondent who is female and prefers HP?

The probability of randomly selecting a respondent who is female and prefers HP is given by the number of females who prefer HP divided by the total number of respondents:

Probability = No. of Females who prefer HP / Total = 110 / 400 = 0.275

Q.1.1.3 What is the probability of selecting a male respondent, given that the preferred brand is Lenovo?

The probability of selecting a male respondent, given that the preferred brand is Lenovo, is given by the number of males who prefer Lenovo divided by the total number of respondents who prefer Lenovo:

Probability = No. of Males who prefer Lenovo / Total No. of respondents who prefer Lenovo = 50 / 110 = 0.4545

Q.1.1.4 What is the probability of selecting a respondent who is male or who prefers HP?

The probability of selecting a respondent who is male or who prefers HP is given by the sum of the probabilities of selecting a male respondent and selecting a respondent who prefers HP, minus the probability of selecting both (to avoid double counting):

Probability = (No. of Males / Total) + (No. of Females who prefer HP / Total) - (No. of Males who prefer HP / Total)

Probability = (160 / 400) + (110 / 400) - (40 / 400) = 0.4 + 0.275 - 0.1 = 0.575

Q.1.1.5 What is the probability of selecting a respondent who does not prefer Lenovo?

The probability of selecting a respondent who does not prefer Lenovo is given by the number of respondents who do not prefer Lenovo divided by the total number of respondents:

Probability = (Total - No. of respondents who prefer Lenovo) / Total

Probability = (400 - 110) / 400 = 290 / 400 = 0.725

The complete question is:

The following contingency table gives the results of a sample survey of South African male and female respondents with regard to their preferred brand of notebook:

                              HP  Lenovo  Dell  Total

No. of Females        110    60   70    240

No. of Males             40    50   70    160

Total                        150    110  140    400

Q.1.1.1 What is the probability of randomly selecting a male respondent from the sample?

Q.1.1.2 What is the probability of randomly selecting a respondent who is female and prefers HP?

Q.1.1.3 What is the probability of selecting a male respondent, given that the preferred brand is Lenovo?

Q.1.1.4 What is the probability of selecting a respondent who is male or who prefers HP?

Q.1.1.5 What is the probability of selecting a respondent who does not prefer Lenovo?

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Answer:

27.5ft

Step-by-step explanation:

a² + b² = c²

Plug in what you have:

a² + 12² = 30²

Get a by itself:

a² = 30² - 12²

Simplify:

a² = 900 - 144

Simplify:

a² = 756

Simplify:

√a = √756

Then you get 27.49 and when you round you get 27.5

The parametric equations for the line of intersection of the planes 4x - 3y + z = 1 and 3x + y - 4z = 4 are:

x = (208 + 70t) / 52

y = (13 + 19t) / 13

z = t

To find the parametric equations for the line of intersection of the planes 4x - 3y + z = 1 and 3x + y - 4z = 4, we can solve these two equations simultaneously.

Step 1: Set up a system of equations:

4x - 3y + z = 1

3x + y - 4z = 4

Step 2: Solve the system of equations to find the values of x, y, and z. One way to solve the system is by using the method of elimination:

Multiply the first equation by 3 and the second equation by 4 to eliminate the y term:

12x - 9y + 3z = 3

12x + 4y - 16z = 16

Subtract the first equation from the second equation:

12x + 4y - 16z - (12x - 9y + 3z) = 16 - 3

12x + 4y - 16z - 12x + 9y - 3z = 13y - 19z = 13

Step 3: Express y and z in terms of a parameter, let's call it t:

13y - 19z = 13

y = (13 + 19z) / 13

We can take z as the parameter t:

z = t

Substituting the value of z in terms of t into the equation for y:

y = (13 + 19t) / 13

Step 4: Express x in terms of t:

From the first equation of the original system:

4x - 3y + z = 1

4x - 3((13 + 19t) / 13) + t = 1

4x - (39 + 57t) / 13 + t = 1

4x - (39 + 57t + 13t) / 13 = 1

4x - (39 + 70t) / 13 = 1

4x = (39 + 70t) / 13 + 1

x = ((39 + 70t) / 13 + 13) / 4

x = (39 + 70t + 169) / 52

x = (208 + 70t) / 52

Therefore, the parametric equations for the line of intersection of the planes 4x - 3y + z = 1 and 3x + y - 4z = 4 are:

x = (208 + 70t) / 52

y = (13 + 19t) / 13

z = t

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Answer:

one solution.            

Answer:

x = -7.5

Step-by-step explanation:

12(x+5) = 4x

12x+ 60 = 4x

60 = -8x

-7.5 = x

Answer:

66.6%

Step-by-step explanation:

You have a 1/6 chance to roll any number. That is a 16.6% chance per number.

So, that means you have a 4/6 (2/3 simplified) probability of not rolling a one or two. That is a 66.6% chance.

[NOTE: The '6' at the end of '16.6%' and '66.6%' is a repeating decimal]

Answer:

x=-5

Step-by-step explanation:

Answer:

try (4,5)

Step-by-step explanation:

that is where the points meet I think it is that I am not sure sorry if it is wrong

Answer:

88 inches

Step-by-step explanation:

formula for circumference: 2pir or pi*diameter

22/7*28=88

88 inches

Answer:

angle C = 36°

Step-by-step explanation:

Fun fact that I found out:

all interior angles of a triangle added together = 180°

5x + 3x + 2x = 180°

combine like terms:

10x = 180°

divide both sides of the equation by 10:

x = 18°

angle C = 2(18°) = 36°

Answer:

A

Step-by-step explanation:

the mean is what occurs most often

A survey of employed adults conducted online by a company on behalf of a research organization revealed the data in the contingency table is as follows:

a) The probability that a randomly selected​ person's gender is​ female is 270/570 or 0.474, which is approximately 47.4%.Formula used: P (Female) = Number of Females/Total Number of Individuals

b) The probability that a randomly selected person feels tense or stressed out at work and is​ female is 145/570 or 0.254, which is approximately 25.4%. Formula used: P (Female and Tense) = Number of Females who are Tense/Total Number of Individuals

c) The probability that a randomly selected person feels tense or stressed out at work or is​ female is: P (Female or Tense) = P(Female) + P(Tense) - P(Female and Tense)P(Tense) = (245/570) or 0.43, which is approximately 43%P(Female or Tense) = 0.47 + 0.43 - 0.254 = 0.646, which is approximately 64.6%.

d) The distinction between the outcomes in​ (b) and​ (c) is that the former shows the likelihood of being female and tense at work, whereas the latter shows the likelihood of being female or tense at work.

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Answer:

2.2y=1x or just x

Step-by-step explanation:

Answer: y=2.2x

Step-by-step explanation:

Answer:

4 2/3 cups

Step-by-step explanation:

Answer:

Well first you must do what's in the parenthesis.

10^2 = 100

100^3 = 1000000

Answer:

F

Step-by-step explanation:

1(10) + 12= 22

2(10) + 12= 32

etc.....

Answer:

175 degrees Fahrenheit

Step-by-step explanation:

We are to find the difference between the two temperatures

125 - (-50)

two minuses gives a plus

125 = 50 = 175

Answer: 15.867 min

Step-by-step explanation:

Given

Ben took [tex]1\ h\ \text{and}\ 23\ min\ 12\ s[/tex] to complete 15 km

While Mike take [tex]1\ hr\ 39\ min\ 4\ s[/tex] to complete the same

converting time into miniutes

Ben time

[tex]\Rightarrow 60+23+\frac{12}{60}=83.2\ min[/tex]

Mike time

[tex]\Rightarrow 60+39+\frac{4}{60}=99.0667\ min[/tex]

So, mike waited for

[tex]\Rightarrow 99.067-83.2=15.867\ min[/tex]

Answer:

5575 cm³

Step-by-step explanation:

The volume of a sphere is V = (4/3)πr³.  If we substitute r = (d/2 where r is the radius and d the diameter), this formula becomes:

                                        πd³

V = (4/3)π·d³/8, or V = -------------

                                           6

and so, if d = 22 cm, the volume is:

        π(22 cm)³

V = ------------------- = 5575 cm³

              6

The mathematical relationship between the relative risk (RR) and the odds ratio (OR) is (c) The relative odds approach.

The mathematical relationship between the relative risk (RR) and the odds ratio (OR) is often described as the relative odds approach.

This approach quantifies the relationship between RR and OR and provides insights into the association between exposure and outcome in observational studies.

The rare disease assumption (a) refers to the assumption made in case-control studies that the odds ratio approximates the relative risk when the outcome is rare.

It is not specifically related to the mathematical relationship between RR and OR.

The built-in bias (b) does not directly relate to the mathematical relationship between RR and OR.

It refers to biases inherent in the study design or data collection process.

Effect modification (d) refers to a situation where the association between an exposure and outcome differs depending on the levels of another variable.

While effect modification can influence the relationship between RR and OR, it is not the specific term used to describe their mathematical relationship.

In summary, the mathematical relationship between RR and OR is best described as the relative odds approach (c), while the other options (a, b, d) are not directly related to this specific relationship.

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(i) For X ~ Laplace(0,1):

E(X) = 0, Var(X) = 2.

(ii) If X ~ Laplace(0,1) and Y = bX + μ:

Y ~ Laplace(μ, b).

(iii) For W ~ Laplace(2,8):

E(W) can be approximated numerically.

Var(W) = 128.

(i) If X ~ Laplace(0,1), we need to find the expected value (E(X)) and variance (Var(X)).

The Laplace(0,1) distribution has μ = 0 and b = 1. Substituting these values into the PDF, we have:

fX(x) = (1/2) * exp(-|x|)

To find E(X), we integrate x * fX(x) over the entire range of X:

E(X) = ∫x * fX(x) dx = ∫x * [(1/2) * exp(-|x|)] dx

Since the Laplace distribution is symmetric about the mean (μ = 0), the integral of an odd function over a symmetric range is zero. Therefore, E(X) = 0 for X ~ Laplace(0,1).

To find Var(X), we use the formula:

Var(X) = E(X^2) - [E(X)]^2

First, let's find E(X^2):

E(X^2) = ∫x^2 * fX(x) dx = ∫x^2 * [(1/2) * exp(-|x|)] dx

Using the symmetry of the Laplace distribution, we can simplify the integral:

E(X^2) = 2 * ∫x^2 * [(1/2) * exp(-x)] dx (integral from 0 to ∞)

Solving this integral, we get:

E(X^2) = 2

Now, substitute the values into the variance formula:

Var(X) = E(X^2) - [E(X)]^2 = 2 - 0 = 2

Therefore, for X ~ Laplace(0,1), E(X) = 0 and Var(X) = 2.

(ii) To show that Y = bX + μ follows a Laplace(μ, b) distribution, we need to find the probability density function (PDF) of Y.

Using the transformation method, let's express X in terms of Y:

X = (Y - μ)/b

Now, calculate the derivative of X with respect to Y:

dX/dY = 1/b

The absolute value of the derivative is |dX/dY| = 1/b.

To find the PDF of Y, substitute the expression for X and the derivative into the Laplace(0,1) PDF:

fY(y) = fX((y-μ)/b) * |dX/dY| = (1/2) * exp(-|(y-μ)/b|) * (1/b)

Simplifying this expression, we get:

fY(y) = 1/(2b) * exp(-|y-μ|/b)

This is the PDF of a Laplace(μ, b) distribution, thus showing that Y ~ Laplace(μ, b).

(iii) For W ~ Laplace(2,8), we need to find E(W) and Var(W).

The PDF of W is given by:

fW(w) = (1/16) * exp(-|w-2|/8)

To find E(W), we integrate w * fW(w) over the entire range of W:

E(W) = ∫w * fW(w) dw = ∫w * [(1/16) * exp(-|w-2|/8)] dw

This integral can be challenging to solve analytically. However, we can approximate the expected value using numerical methods or software.

To find Var(W), we can use the property that the variance of the Laplace distribution is given by 2b^2, where b is the scale parameter.

Var(W) = 2 * b^2

= 2 * (8^2)

= 2 * 64

= 128

Therefore, Var(W) = 128 for W ~ Laplace(2,8).

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Answer:

1st, 2nd, 3rd

Step-by-step 1explanation:

30+40+5=75

30+40=70

70+5=75

20+1+50+4

=20+50=70

1+4=5

70+5=75

50+30-5  

50+30=80

80-5=75

I hope this helps :)