A study was conducted in order to estimate ?, the mean number of weekly hours that U.S. adults use computers at home. Suppose a random sample of 81 U.S. adults gives a mean weekly computer usage time of 8.5 hours and that from prior studies, the population standard deviation is assumed to be ? = 3.6 hours.
A similar study conducted a year earlier estimated that ?, the mean number of weekly hours that U.S. adults use computers at home, was 8 hours. We would like to test (at the usual significance level of 5%) whether the current study provides significant evidence that this mean has changed since the previous year.
Using a 95% confidence interval of (7.7, 9.3), our conclusion is that:
a. the current study does provide significant evidence that the mean number of weekly hours has changed over the past year, since 8 falls outside the confidence interval.
b. the current study does not provide significant evidence that the mean number of weekly hours has changed over the past year, since 8 falls outside the confidence interval.
c. the current study does provide significant evidence that the mean number of weekly hours has changed over the past year, since 8 falls inside the confidence interval.
d. the current study does not provide significant evidence that the mean number of weekly hours has changed over the past year, since 8 falls inside the confidence interval.
e. None of the above. The only way to reach a conclusion is by finding the p-value of the test.

Answer:

You dind't include the answer choices but it should look something like

[tex]50000(.8)^t[/tex]

Answer:

Step-by-step explanation:

Speed = (15 mi)/hr × (1.6 km)/mi = (24 km)/hr

:::::

(4 hr) × (24 km)/hr = 96 km

Answer:

The answer is that the runner can run 10 miles in 70 minutes.

Step-by-step explanation:

To solve for the number of miles that the runner can run in 70 minutes, start by setting up the information given from the problem in the form of a proportion.

A proportion is an equation which defines that the two given ratios are equivalent to each other. In other words, the proportion states the equality of the two fractions or the ratios. In a proportion, if two sets of given numbers are increasing or decreasing in the same ratio, then the ratios are said to be directly proportional to each other.

The proportion for this problem will look like [tex]\frac{2 miles}{14 minutes}=\frac{x}{70 minutes}[/tex]. (x) will be used as the variable for the number of miles that the runner can run in 70 minutes.  

To solve the proportion, start by cross multiplying to form an equation, and the equation will look like [tex](14)(x)=(2)(70)[/tex]. Next, simplify the equation, which will look like [tex](14)(x)=140[/tex]. Then, solve the equation by dividing both sides of the equation by 14, and it will look like [tex]x=10[/tex]. The final answer is that the runner can run 10 miles in 70 minutes.

Answer:

total = m/n * c

m/n gives u the number of pounds u have bought, multplied by the cost of the candies per pound gives u the total amount of money she paid

Answer:

There are 666 numbers multiple of 3 in the interval.

Step-by-step explanation:

Multiples of 3:

A number is a multiple of 3 if the sum of it's digits is a multiple of 3.

Range [2,2000]:

First multiple of 3 in the interval: 3

Last: 1998

How many:

[tex]1 + \frac{1998 - 3}{3} = 1 + 665 = 666[/tex]

There are 666 numbers multiple of 3 in the interval.

Answer: [tex]x=12[/tex]

Step-by-step explanation:

[tex]f(x)=16x-30\\g(x)=14x-6[/tex]  are the equations that you've given us.

Now if we plot these two equations on the graph we notice there's an intersection at (12,162). Therefore meaning that [tex]x=12[/tex].

We can prove that by doing the following calculations to prove that both sides are equal to each other.

The left side of the equal sign:

Step 1: Write the equation down:

[tex]16x-30[/tex]

Step 2: Substitute x for the numerical value we found.

[tex]16(12)-30[/tex]

Step 3: We will multiply [tex]16*20[/tex] first, giving us 192.

[tex]192-30[/tex]

Step 4: Subtract 192 from 30. Which gives us 162.

[tex]162[/tex]

The right side of the equal sign:

Step 1: Write the equation down:

[tex]14x-6[/tex]

Step 2: Substitute x for the numerical value we found.

[tex]14(12)-6[/tex]

Step 3: We will multiply [tex]14*12[/tex] first, giving us 168.

[tex]168-6[/tex]

Step 4: Subtract 168 from 6. Which gives us 162.

[tex]162[/tex]

We know that [tex]x=12[/tex] because when substituting x with 12, we get 162 on both sides. Therefore making this statement true and valid.

[tex]162=162[/tex]

Answer:

(483.981 ; 504.019)

Step-by-step explanation:

Given :

σ = 100

Sample size, n = 661

xbar = 494

We use the Z distribution since we are working with the population standard deviation ;

C.I = xbar ± (Zcritical * σ/√n)

Zcritical at 99% = 2.576

C.I = 494 ± (2.576 * 100/√661)

C.I = 494 ± 10.019

Lower boundary = (494−10.019) = 483.981

Upper boundary = (494+10.019) = 504.019

C.I = (483.981 ; 504.019)

Answer:

x = 65

Step-by-step explanation:

x = √(25×(25+144))

x = √(25×169)

x = 5×13

x = 65

Answered by GAUTHMATH

Answer:

Option b, (4,2)

Option d, (8,4)

Option e, (12,6)

Answered by GAUTHMATH

Answer:

Option b, (4,2)

Option d, (8,4)

Option e, (12,6)

Step-by-step explanation:

the person above me is correct

Answer:

-1/3

Step-by-step explanation:

Perpendicular lines have slopes that multiply to -1

a*b = -1

3 * b = -1

b = -1/3

The slope of line b is -1/3

Answer:

Between 79.2 and 84.8.

Step-by-step explanation:

The Empirical Rule states that, for a normally distributed random variable:

Approximately 68% of the measures are within 1 standard deviation of the mean.

Approximately 95% of the measures are within 2 standard deviations of the mean.

Approximately 99.7% of the measures are within 3 standard deviations of the mean.

In this problem, we have that:

Mean of 82, standard deviation of 2.8.

In what range would you expect to find the FBG of 68% of your study participants?

By the Empirical Rule, within 1 standard deviation of the mean, so:

82 - 2.8 = 79.2

82 + 2.8 = 84.8

Between 79.2 and 84.8.

Answer:

27 inch

Step-by-step explanation:

Current perimeter=18

New perimeter=18*1.5=27 in

Answer:

Step-by-step explanation:

It's never negative.

D is indeed correct, the function's values never go below 0, meaning never below the x-axis

( x + 1 )( x )( x - 5 ) =

( x + 1 )( x - 5 )( x ) =

( x^2 - 4x - 5 )( x ) =

x^3 - 4x^2 - 5x

Step-by-step explanation:

the other answer is basically correct.

as the simplest form you create 3 terms for the three given solutions (= the values for when the equation equals 0).

but maybe you need to add " = 0" for the full equation.

Answer:

y  ≤  9

Step-by-step explanation:

3y - 11 ≤ 2y - 2

Subtract 2y from each side

3y-2y - 11 ≤ 2y-2y - 2

y - 11 ≤  - 2

Add 11 to each side

y - 11+11 ≤  - 2+11

y  ≤  9

Answer:

[tex]y \leqslant 9[/tex]

Step-by-step explanation:

[tex]3y - 11 \leqslant 2y - 2 \\ 3y - 2y \leqslant 11 - 2 \\ y \leqslant 9[/tex]

Answer:

5≤x≤7

Step-by-step explanation:

For a given function f(x), the average rate of change in a given interval:

a ≤ x ≤ b

is given by:

[tex]r = \frac{f(b) - f(a)}{b - a}[/tex]

Here we have:

f(x) = 4*log(x + 2)

And we want to see which interval has the smallest average rate of change, so we just need fo find the average rate of change for these 4 intervals.

1)  1≤x≤3

here we have:

[tex]r = \frac{f(3) - f(1)}{3 - 1} = \frac{4*log(3 + 2) - 4*log(1 + 2)}{2} = 0.44[/tex]

2)  5≤x≤7

[tex]r = \frac{f(7) - f(5)}{7 - 5} = \frac{4*log(7 + 2) - 4*log(5 + 2)}{2} = 0.22[/tex]

3) 3≤x≤5

[tex]r = \frac{f(5) - f(3)}{5 - 3} = \frac{4*log(5 + 2) - 4*log(3 + 2)}{2} = 0.29[/tex]

4) −1≤x≤1

[tex]r = \frac{f(1) - f(-1)}{1 - (-1)} = \frac{4*log(1 + 2) - 4*log(-1 + 2)}{2} = 0.95[/tex]

So we can see that the smalles average rate of change is in 5≤x≤7

Explanation:

A = values on the die greater than 1

A = {2,3,4,5,6}

B = values on the die less than 5

B = {1,2,3,4}

Union those two sets together

C = A u B = {1,2,3,4,5,6}

Effectively, we get every possible value on the die. This is due to the "or" keyword. If it was "and", then it would be a difference story.

So the probability of getting anything in set C is 100% or just 1. We have guaranteed certainty we'll have this event happen.

Answer:

a) 0.0156 = 1.56% probability that all children will develop the disease.

b) 0.4219 = 42.19% probability that only one child will develop the disease.

c) 0.1406 = 14.06% probability that the third children will develop the disease, given that the first two did not.

Step-by-step explanation:

For each children, there are only two possible outcomes. Either they carry the disease, or they do not. The probability of a children carrying the disease is independent of any other children, which means that the binomial probability distribution is used to solve this question.

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.

The probability that their offspring will develop the disease is approximately .25.

This means that [tex]p = 0.25[/tex]

Three children:

This means that [tex]n = 3[/tex]

Question a:

This is P(X = 3). So

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

[tex]P(X = 3) = C_{3,3}.(0.25)^{3}.(0.75)^{0} = 0.0156[/tex]

0.0156 = 1.56% probability that all children will develop the disease.

Question b:

This is P(X = 1). So

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

[tex]P(X = 1) = C_{3,1}.(0.25)^{1}.(0.75)^{2} = 0.4219[/tex]

0.4219 = 42.19% probability that only one child will develop the disease.

c. The third child will develop Tay–Sachs disease, given that the first two did not.

Third independent of the first two, so just multiply the probabilities.

First two do not develop, each with 0.75 probability.

Third develops, which 0.25 probability. So

[tex]p = 0.75*0.75*0.25 = 0.1406[/tex]

0.1406 = 14.06% probability that the third children will develop the disease, given that the first two did not.

Answer:

0.25

Step-by-step explanation:

16/4 = 4

4/4 = 1

1/4 = 0.25

0.25/4 = 0.0625

0.0625/4 = 0.015625

give me brainliest please:)

The LEAST selling price of the laptop should be ;

$1024.1 in other to avoid loss.

Price of laptop = $770

Tax = 20%

VAT = 13%

TO avoid loss ;

both the VAT percentage and TAX must be added to the price of the laptop:

Total percentage = VAT + TAX = (20 + 13) = 33%

THEREFORE, Least selling price should be :

Price of laptop * (1 + 33%)

770 * 1.33

= $1024.1

Learn more about TAX :

https://brainly.in/question/31818297

Answer:

0.6524 = 65.24% probability that the runner will average between 146 and 150 minutes in these 49 marathons.

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.

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.

Average of 147 minutes with a standard deviation of 12 minutes.

This means that [tex]\mu = 147, \sigma = 12[/tex]

Consider 49 of the races.

This means that [tex]n = 49, s = \frac{12}{\sqrt{49}} = \frac{12}{7} = 1.7143[/tex]

Find the probability that the runner will average between 146 and 150 minutes in these 49 marathons.

This is the p-value of Z when X = 150 subtracted by the p-value of Z when X = 146. So

X = 150

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

By the Central Limit Theorem

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

[tex]Z = \frac{150 - 147}{1.7143}[/tex]

[tex]Z = 1.75[/tex]

[tex]Z = 1.75[/tex] has a p-value of 0.9599

X = 146

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

[tex]Z = \frac{146 - 147}{1.7143}[/tex]

[tex]Z = -0.583[/tex]

[tex]Z = -0.583[/tex] has a p-value of 0.3075.

0.9599 - 0.3075 = 0.6524.

0.6524 = 65.24% probability that the runner will average between 146 and 150 minutes in these 49 marathons.

Answer: The area is 22 17/64.

Step-by-step explanation:

base = 7 1/8 = 57/8

height = 6 1/4 = 25/4

area = 1/2*b*h

= 1/2*57/8*25/4

= 1425/64

= 22 17/64

Answer:

[tex]x = 2[/tex]

[tex]S_n = 63[/tex]

Step-by-step explanation:

Given

[tex]a_1 = x + 1[/tex]

[tex]a_2 = 4x -2[/tex]

[tex]a_3 = 6x -3[/tex]

[tex]a_n = 18[/tex]

Solving (a): x

To do this, we make use of common difference (d)

[tex]d = a_2 - a_1[/tex]

[tex]d = a_3 - a_2[/tex]

So, we have:

[tex]a_3 - a_2 = a_2 - a_1[/tex]

Substitute known values

[tex](6x - 3) - (4x - 2) = (4x - 2) - (x + 1)[/tex]

Remove brackets

[tex]6x - 3 - 4x + 2 = 4x - 2 - x - 1[/tex]

Collect like terms

[tex]6x - 4x- 3 + 2 = 4x - x- 2 - 1[/tex]

[tex]2x- 1 = 3x- 3[/tex]

Collect like terms

[tex]2x - 3x = 1 - 3[/tex]

[tex]-x = -2[/tex]

[tex]x = 2[/tex]

Solving (b): Sum of progression

First, we calculate the first term

[tex]a_1 = x + 1[/tex]

[tex]a_1 = 2 + 1 = 3[/tex]

Next, calculate d

[tex]d = a_2 - a_1[/tex]

[tex]d = (4x - 2) - (x +1)[/tex]

[tex]d = (4*2 - 2) - (2 +1)[/tex]

[tex]d = 6 - 3 = 3[/tex]

Next, we calculate n using:

[tex]a_n = a + (n - 1)d[/tex]

Where:

[tex]a_n = 18[/tex]

[tex]d = 3; a = 3[/tex]

So:

[tex]18 = 3 +(n - 1) * 3[/tex]

Subtract 3 from both sides

[tex]15 = (n - 1) * 3[/tex]

Divide both sides by 3

[tex]5 = n - 1[/tex]

Add 1 to both sides

[tex]6 = n[/tex]

[tex]n = 6[/tex]

The sum of the progression is:

[tex]S_n = \frac{n}{2} * [a + a_n][/tex]

So,, we have:

[tex]S_n = \frac{6}{2} * [3 + 18][/tex]

[tex]S_n = 3 * 21[/tex]

[tex]S_n = 63[/tex]

Answer:

972pi in ^3

Step-by-step explanation:

We need to find the volume of the sphere

V = 4/3 pi r^3

The diameter is 18

r = d/2 = 18/2 = 9

V = 4/3 pi ( 9)^3

V = 972pi in ^3

Answer:

Angle T is congruent to Angle Z

Step-by-step explanation:

Since the 2 triangles are equal, that means that each pair of angles are also congruent. To know which angles are congruent, you check th order of how the triangles are named. Ex. Angle Q is congruent to Angle A, Angle P is congruent to Angle R, and Angle T is congruent to Angle Z.

Answer:

x = -5/2 y +25/2

Step-by-step explanation:

5y + 2x = 25

Subtract 5y from each side

5y + 2x -5y= -5y+25

2x = -5y +25

Divide by 2

2x/2 = -5y/2 +25/2

x = -5/2 y +25/2

Answer:

X-(-7)

Step-by-step explanation:

If you are subtract by a negative number it turns it into a positive. It would look like this: X+(+7)

Answer: y = 0 and x = -1

Answer:

48 ÷ 60 = 4/5

Step-by-step explanation:

4/5 is the answer

Answer:

[tex]\frac{1}{30}[/tex]

Step-by-step explanation:

We require the number of minutes in a day.

i hour = 60 minutes

24 hours = 24 × 60 = 1440 minutes ( 24 hours in 1 day )

Then

fraction = [tex]\frac{48}{1440}[/tex] ( divide numerator/ denominator by 12 )

            = [tex]\frac{4}{120}[/tex] ( divide numerator/ denominator by 4 )

            = [tex]\frac{1}{30}[/tex]

Taking into account the definition of axis of simmetry and vertexn the axis of symmetry is x = 5.

So, first of all, you must know what a quadratic function is. Every quadratic function can be expressed as follows:

f(x) = a*x² + b*x + c

where a, b and c are real numbers.

The graph of a quadratic function is a parabola. Every parabola is a symmetric curve with respect to a horizontal line called the axis of symmetry.

That is, the axis of symmetry is an imaginary line that passes through the middle of the parabola and divides it into two halves that are equal of each other.

In other words, the axis of symmetry of a parabola is a vertical line that divides the parabola into two equal halves and always passes through the vertex of the parabola.

The point of intersection of the axis of symmetry with the parabola is called the vertex.

The axis of symmetry always passes through the vertex of the parabola. The x-coordinate of the vertex is the equation of the axis of symmetry of the parabola.

Being the vertex of the quadratic function (5,7), where the vertex on the x-axis has a value of 5 and on the y-axis a value of 7, the axis of symmetry is x = 5.

Learn more with this examples: