Identify the type of observational study​ (cross-sectional, retrospective, or​ prospective) described below. A research company uses a device to record the viewing habits of about 7500 ​households, and the data collected today will be used to determine the proportion of households tuned to a particular sports program. Which type of observational study is described in the problem​ statement?

Step-by-step explanation:

Subtract 2690 from 3780

3780

-2690

=1090

Answer:

|Z| < 2, which means that it would not be unusual for the mean of a sample of 3 to be 115 or more.

Step-by-step explanation:

To solve this question, we need to understand the normal probability distribution and the central limit theorem.

Normal Probability Distribution:

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

In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the z-score of a measure X is given by:

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

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 p-value, we get the probability that the value of the measure is greater than X.

If [tex]|Z| > 2[/tex], the value of X is considered to be unusual.

Central Limit Theorem

The Central Limit Theorem establishes that, for a normally distributed random variable X, with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean [tex]\mu[/tex] and standard deviation [tex]s = \frac{\sigma}{\sqrt{n}}[/tex].

For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.

Assume that a population is normally distributed with a mean of 100 and a standard deviation of 15.

This means that [tex]\mu = 100, \sigma = 15[/tex]

Sample of 3

This means that [tex]n = 3, s = \frac{15}{\sqrt{3}}[/tex]

Would it be unusual for the mean of a sample of 3 to be 115 or more? Why or why not?

We have to find the z-score.

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

By the Central Limit Theorem

[tex]Z = \frac{X - \mu}{s}[/tex]

[tex]Z = \frac{115 - 100}{\frac{15}{\sqrt{3}}}[/tex]

[tex]Z = 1.73[/tex]

|Z| < 2, which means that it would not be unusual for the mean of a sample of 3 to be 115 or more.

first and last one i think

9514 1404 393

Answer:

  A, C

Step-by-step explanation:

A: -3 -(-8) = -3 +8 = 5

B: -2 -3 = -5

C: 1 -(-4) = 1 +4 = 5

D: 7 -(-2) = 7 +2 = 9

__

Differences A and C are 5.

Answer: A: -3- (-8)

B:1 -(-4)

Step-by-step explanation:

in A your subtracting them in B your adding them

Answer:

Its B

Step-by-step explanation:

Mark as Brainllest!!

Answer:

Step-by-step explanation:

Wage = rate / hr * the number of hours worked.

Wage = ?

rate = 15.45

time = 29.25 hours

Wage = 15.45 * 29.25

Wage = 451.91

Step-by-step explanation:

[tex] \sqrt{15} = 3.872983346 = 3.88[/tex]

Answer:

= 5 * NORMINV(RAND(), 35, 5)

Step-by-step explanation:

From the given information:

The total weekly profit is achieved by the multiplication of the unit profit (5) and the weekly demand.

Here, the weekly demands obey a normal distribution where the mean = 35 and the standard deviation = 5.

Using the Excel Formula:

The weekly profit can be computed as:

= 5 * NORMINV(RAND(), 35, 5)

Answer:

34 cm

Step-by-step explanation:

The radius is half of the diameter, so 17 cm is half of 34 cm.

Diameter = 34 cm

Answer: In the picture from the basic music theory website's page on a-sharp  major scale

Step-by-step explanation: music theory

Answer:

c

Step-by-step explanation:

4/6 is reduced to two thirds

Answer:

40

Step-by-step explanation:

If you take 15, and divide it by the 3 out of the 3/8 left, you get 5. You then multiply 5 by 8 to get the full amount of candies she had before sharing, 40.

I hope this helped!

Thanks!

Your friend in answering,

~Steve

Answer:

40.

Step-by-step explanation:

If 15 candies are the rest of 3/8, then the total candies were 40.

Answer:

observational study

Step-by-step explanation:

Answer:

nnmb cgchmfxmgfmv vb  ,  mnio qrstuvwxyz

abcdefghijklmnoprstuvxxyz

Step-by-step explanation:

now i know my abcs next time wont you sing with me

Answer:

[tex]150[/tex] cubic centimeters

Step-by-step explanation:

Volume for triangular prism is  [tex]V=\frac{1}{2} bhl[/tex]

[tex]V=\frac{1}{2}(6)(5)(10)[/tex]

[tex]V=\frac{1}{2} (300)[/tex]

[tex]V=150[/tex]

Hope this helps

Answer:

150 cubic centimeters

Step-by-step explanation:

The formula for the volume of a Triangular prism:

A=1/2*b*h*l

plug everything in

1/2*6*5*10=150 Cubic centimeters

Answer:

0.0475 = 4.75% probability a pizza is delivered for free.

0.2955 = 29.55% probability that more than 2 were delivered for free.

The delivery time should be advertised as 32 minutes.

Step-by-step explanation:

To solve this question, we need to understand the binomial distribution and the normal distribution.

Binomial probability distribution

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

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

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

[tex]C_{n,x} = \frac{n!}{x!(n-x)!}[/tex]

And p is the probability of X happening.

Normal Probability Distribution:

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

In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the z-score of a measure X is given by:

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

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 p-value, we get the probability that the value of the measure is greater than X.

Normally distributed with mean 25 minutes and standard deviation 3 minutes.

This means that [tex]\mu = 25, \sigma = 3[/tex]

What is the probability a pizza is delivered for free?

More than 30 minutes, which is 1 subtracted by the p-value of Z when X = 30.

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

[tex]Z = \frac{30 - 25}{3}[/tex]

[tex]Z = 1.67[/tex]

[tex]Z = 1.67[/tex] has a p-value of 0.9525

1 - 0.9525 = 0.0475

0.0475 = 4.75% probability a pizza is delivered for free

What is the probability that more than 2 were delivered for free?

Multiple pizzas, so the binomial probability distribution is used.

0.0475 probability a pizza is delivered for free, which means that [tex]p = 0.0475[/tex]

40 pizzas, which means that [tex]n = 40[/tex]

This probability is:

[tex]P(X > 2) = 1 - P(X \leq 2)[/tex]

In which

[tex]P(X \leq 2) = P(X = 0) + P(X = 1) + P(X = 2)[/tex]

So

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

[tex]P(X = 0) = C_{40,0}.(0.0475)^{0}.(0.9525)^{40} = 0.1428[/tex]

[tex]P(X = 1) = C_{40,1}.(0.0475)^{1}.(0.9525)^{39} = 0.2848[/tex]

[tex]P(X = 2) = C_{40,2}.(0.0475)^{2}.(0.9525)^{38} = 0.2769[/tex]

Then

[tex]P(X \leq 2) = P(X = 0) + P(X = 1) + P(X = 2) = 0.1428 + 0.2848 + 0.2769 = 0.7045[/tex]

[tex]P(X > 2) = 1 - P(X \leq 2) = 1 - 0.7045 = 0.2955[/tex]

0.2955 = 29.55% probability that more than 2 were delivered for free.

If the company wants to reduce the proportion of pizzas that are delivered free to 1%, what should the delivery time be advertised as?

The 99th percentile, which is X when Z has a p-value of 0.99, so X when Z = 2.327.

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

[tex]2.327 = \frac{X - 25}{3}[/tex]

[tex]X - 25 = 2.327*3[/tex]

[tex]X = 32[/tex]

The delivery time should be advertised as 32 minutes.

Answer: The coefficient before x^4 is 60

Step-by-step explanation:

Hey! So I am not an expert at this, but you have to use the binomial theorem

I have attached of the Pascals Triangle (one shows the row numbering as well)

Basically in a pascal triangle, you add the two numbers above it to get the next number below

As you can see, the rows start from 0 instead of 1

The 6th row contains the numbers 1, 6, 15, 20, 15, 6, 1 which would be the coefficient terms

NOTE: the exponents always add to 6, the first term starts at 6 and decrease it's exponent by 1 each time (6, 5, 4, 3, 2, 1, 0) and the second term increases it's exponent by 1 each time (0, 1, 2, 3, 4, 5, 6)

Using this information the third term from the sixth row (15) would be where it is x^4 (I have circled it on the second image)

It would be 15 × 2^4 × (1/2)^2 = 60

The reason why it is 2^4 and (1/2)^2 is because the third term has the exponents 4 and 2 (bolded on the NOTE) which means that the first term must be put to the power of 4 and the second term must be put to the 2nd power

Sorry for the lousy explanation. I really hope this makes sense! Let me know if this helped :)

Answer:

a) The probability that a randomly chosen specimen has an acceptable hardness is 0.7938.

b) If the acceptable range of hardness is (70-c, 70+c), then the value of c would 95% of all specimens have an acceptable hardness of 5.88.

c) Expected number of acceptable specimens among the ten is 7.938.

d) Binomial with n = 10 and p = P(X < 73.84)

[tex]p = P(Z <(73.84 - 70) / 3 ) = P(Z < 1.28) = 0.8997\\\\P(X <= 8) = 1 - P(X = 9) - P(X = 10)\\= 0.2650635[/tex]

Step-by-step explanation:

a )

[tex]P(67 < X< 75) = P( (67 - 70) / 3 < X < (75 - 70) / 3 )\\\\= P( - 1 < Z < 1.67) = 0.9525 - 0.1587 = 0.7938[/tex]

b )

[tex]c = 1.96 * 3 = 5.88[/tex]                    { Since Z = 1.96 for 95% CI refer table.}

c )

Expected number of acceptable specimens among the ten [tex]= 10 * P(67 < X< 75) \\\\= 10 * 0.7938 = 7.938[/tex]

d )

Binomial with n = 10 and p = P(X < 73.84)

[tex]p = P(Z <(73.84 - 70) / 3 ) = P(Z < 1.28) = 0.8997\\\\P(X <= 8) = 1 - P(X = 9) - P(X = 10)\\= 0.2650635[/tex]

Answer:

C.4/9

Step-by-step explanation:

You add the black marbles, blue marbles, and the white marbles together, which equal 18. Out of the 18 marbles, 8 of them are white so it would be 8/18.

but you have to simplify it. 8 and 18 have 2 as the greatest common factor. 8 divided by 2 is 4 and 18 divided by 2 is 9. Finally its 4/9 since you cant simplify it even more.

Answer:

7

Step-by-step explanation:

481 + 223

approximately 481 =5

223 =2

5+2=7

Answer:

7

Step-by-step explanation:

Hey there! The topic for this problem is Limit of Function!

As for the question, we are given the quadratic function and we have to find the limit, the value that approaches to a.

[tex] \large \boxed{lim_{x \longrightarrow a} f(x)}[/tex]

We call this, "The limit of f(x) when x approaches a."

Then you may ask, "How do we find the limit of function?". That is a very nice question! The answer to your problem is just substitute x-value in. Although this substitution method only applies when the approaching value doesn't make the denominator to 0. I believe that in the beginning of Limit topic, we learn how to find or evaluate the basic limit that only requires substitution.

So from the question, we receive:

[tex] \large{lim_{x \longrightarrow 2} ( {x}^{2} - 3x - 1)}[/tex]

Next step is to substitute x = 2 in the function.

[tex] \large{lim_{x \longrightarrow 2} ( {2}^{2} - 3(2) - 1)}[/tex]

Evaluate the value.

[tex] \large{lim_{x \longrightarrow 2} ( 4 - 6 - 1)} \\ \large{lim_{x \longrightarrow 2} ( - 3)}[/tex]

Cancel the limit out and there you have it!

[tex] \large \boxed{ - 3}[/tex]

Answer

Now whenever you learn limit, you must know that limit is when we substitute the approaching value. That means x —> 2 is not x = 2 but x approaches 2.

Regarding the limit, any questions and doubts can be asked through comment and I will get back to you soon!

Thank you for using Brainly and I hope you have a fantastic day! Good luck on the assignment.

Answer:

The Third one

Step-by-step explanation:

Your Welcome :)

Graph of the function is attached below.

Correct option is D.

As the name suggests, the exponential function contains an exponent. Note, however, that the exponential function has a constant as its base and a variable as its exponent, not vice versa (if a function has a variable as its base and a constant as its exponent, it is a power function). The exponential function can be in one of the following forms:

Definition of exponential function

In mathematics, an exponential function is a function of the form f(x) = aˣ. where "x" is a variable and "a" is a constant  called the base of the function, which must be greater than 0.

Given, exponential function

f(x) = (1/4)4ˣ

exponential function is defined for x∈R

Putting x = 0

f(0) = (1/4)4⁰

f(0) = 1/4

Point on curve is (0,1/4)

Putting x = 1

f(1) = (1/4)4¹

f(1) = (1/4)4

f(1) = 1

Point on curve is (1,1)

Putting x = 2

f(2) = (1/4)4²

f(2) = (1/4)16

f(2) = 4

Point on curve is (2,4)

Putting x = 3

f(3) = (1/4)4³

f(3) = (1/4)64

f(3) = 16

Point on curve is (3,16)

Point (0, 1/4), (1, 1), (2, 4), (3, 16) can be used to draw graph of the function.

Hence, graph of the function is drawn as follows.

Learn more about exponential function here:

https://brainly.com/question/14355665

#SPJ7

Answer:

- 54

Step-by-step explanation:

11 c + 5 a - 8

11 × -6 + 5 × 4 - 8 (given :- a = 4 and b = -6)

- 66 + 20 - 8

- 54

Step-by-step explanation:

Is it helpful ?

plz let me know

Answer:

[tex]\frac{q - r}{m- n} = \frac{p - s}{m - n}[/tex]

Step-by-step explanation:

Given

See attachment for parallelogram

Required

Proof that ABCD is a parallelogram

We know that opposite sides are equal and parallel.

First, we calculate the slope of BC

[tex]m = \frac{y_2 - y_1}{x_2 - x_1}[/tex]

So, we have:

[tex]m = \frac{q - r}{m- n}[/tex]

Next, the slope of AD using:

[tex]m = \frac{y_2 - y_1}{x_2 - x_1}[/tex]

So, we have:

[tex]m = \frac{p - s}{m - n}[/tex]

For ABCD to be a parallelogram; then:

[tex]\frac{q - r}{m- n} = \frac{p - s}{m - n}[/tex]

Answer:

k=7

Step-by-step explanation:

2x+3y=k

2(2)+3(1)=k

4+3=k

k=7

Answer:

7.

Step-by-step explanation:

Substitute x = 2 and y = 1 into the given equation:

2(2) + 3(1) = k

4 + 3 = k

k = 7.

Answer: B ACE is similar to DCB

Step-by-step explanation:

Answer:

-3

Step-by-step explanation:

in these equations the slope is multiplied by x which is -3 in this one.

Answer:

[tex]-3[/tex]

Step-by-step explanation:

The equation of a line is [tex]y=mx+b[/tex], and m is the gradient which is the slope. Hence, the number with x is the slope, which is [tex]-3[/tex].

Hope that helped.