9.2 An electrical firm manufactures light bulbs that have a length of life that is approximately normally distributed with a standard deviation of 40 hours. If a sample of 30 bulbs has an average life of 780 hours, find a 96% confidence interval for the population mean of all bulbs produced by this firm.

Answer:

32

Step-by-step explanation:

Answer:

1. Number of classes used are 7 with 5 class interval.

Step-by-step explanation:

Note: See the attached files for the tables and answers to questions 2, 3, 4 and 5.

Answer:

percentage change in weight ≈ 10%

Step-by-step explanation:

The dog weighed 48 kg after a diet and after an exercise program the dog had a weight of 43 kg. This means the dog loss weight since the dog weight decreased from an initial value of 48 kg to 43 kg. The decrease in weight can be calculate as

decrease in weight = original weight - new weight

original weight  = 48 kg

new weight = 43 kg

decrease in weight = 48 - 43 = 5 kg

Since the weight decrease their will be a percentage decrease in weight.

% decrease = decrease in weight/original weight × 100

% decrease = 5/48 × 100

% decrease = 500/48

% decrease = 10. 42666666667

percentage change in weight ≈ 10%

Answer: False

Step-by-step explanation:

We can write tan(x) = sin(x)/cos(x)

if cos(x) tends to 1, and sin (x) tends to 0 (this happens aronund the point x = 0)

then we have:

Tan(x) = 0/1 = 0

Then the statement is false, as cos(x) approaches 1 and sin(x) approaches 0, tan(x) also approaches 0.

Answer:

342 square meters

Step-by-step explanation:

Consider the length of j;

[tex]j * 9 * 9 = 405,\\j = 405 / 81,\\j = 5 meters[/tex]

Applying the volume of a rectangular prism formula length * width * height = volume, we noted that 9, 9, and j corresponded to the length, width, and height of the rectangular prism and made it equivalent to the volume. Doing so, we solved for j. Now let us solve for the surface area;

[tex]Area of 1st Face = 5 * 9 = 45,\\Area of 2nd Face = 9 * 9 = 81,\\Area of 3rd Face = 5 * 9 = 45,\\\\Surface Area = 2 * ( 45 ) + 2 * ( 81 ) + 2 * ( 45 ) = 342 square meters[/tex]

Opposite faces are equal in terms of their area, so by finding the area of 3 faces, we multiply their area each by 2 to result in the total surface area!

Here is the correct question.

The manufacturer of a smart watch claims that individuals who pay attention to how many steps they take per day will inadvertently take more steps per day than individuals who pay no attention to how many steps they take per day. To investigate this claim, the manufacturer conducts a study to estimate the difference in the mean number of steps taken by those that pay attention to how many steps they take per day and those that do not. To do so, 40 volunteers are recruited. Half of the volunteers are randomly assigned to receive a smart watch and are taught how to use it to track their steps. The other half of the volunteers are given a wristband to wear, but are not informed that the wristband is tracking their steps. The volunteers are monitored for 30 days. The mean and standard deviation of the number of steps taken per day are computed for each group. Here are the data:

                                           [tex]n[/tex]                     [tex]\bar x[/tex]                  [tex]S_x[/tex]

Pay attention                    20                 10,244            1,580

Do not pay attention        20                 8.,648            2,350

Which of the following is a 99% confidence interval for the difference in the mean number of steps taken by all people like these that do and do not pay attention to the number of steps they take per day using df - 19 ?

[tex](A) \ 1596 \ \pm 2.861 \sqrt{ \dfrac{1580^2}{20} + \dfrac{2350^2}{20}} \\ \\ \\ (B) \ 1596 \ \pm 2.861 \sqrt{ \dfrac{1580^2}{20} - \dfrac{2350^2}{20}} \\ \\ \\ (C) \ 1596 \pm 2.576 \sqrt{ \dfrac{1580^2}{20} + \dfrac{2350^2}{20}} \\ \\ \\ (D) 1596 \pm 2.576 ( \dfrac{1580^2}{\sqrt{20}} + \dfrac{2350^2}{\sqrt{20}}) \\ \\ \\ (E) 1596 \pm 2.576 ( \dfrac{1580^2}{\sqrt{20}} - \dfrac{2350^2}{\sqrt{20}})[/tex]

Answer:

[tex]\mathbf{(A) \ 1596 \ \pm 2.861 \sqrt{ \dfrac{1580^2}{20} + \dfrac{2350^2}{20}}}[/tex]

Step-by-step explanation:

Given that :

significance level [tex]\alpha = \mathbf{0.01}[/tex]

From the Given data;

Using Excel with the function : TINV(0.01,19);

Critical value t* = 2.861

The margin of error can now be represented by the illustration:

Margin of error = [tex]t^* \sqrt{ \dfrac {s_1 ^2}{n_1} + \dfrac {s_2 ^2}{n_2}[/tex]

Lower Limit =  [tex](\bar x_1 - \bar x_2)- (Margin \ of \ error)[/tex]

Upper Limit =  [tex](\bar x_1 - \bar x_2)+ (Margin \ of \ error)[/tex]

Thus; the confidence interval for the difference in the mean number of steps taken by all people like these that do and do not pay attention to the number of steps they take per day using df - 19 is:

[tex]\mathbf{(A) \ 1596 \ \pm 2.861 \sqrt{ \dfrac{1580^2}{20} + \dfrac{2350^2}{20}}}[/tex]

Answer:

[tex] p =\frac{7}{51}= 0.1372[/tex]

And then the probability that is NOT from sport temas using the complement rule is given by:

[tex] q = 1-p =1- \frac{7}{51}= 0.8627[/tex]

And if we convert that into % we got:

[tex] 0.8627 *100= 86.27\%[/tex]

Approximately 86.27% of the floats were NOT sports teams

Step-by-step explanation:

For this case we can begin finding the % of floats that were from sport tems using the Laplace definition of probability given by:

[tex]p = \frac{Possible}{Total}[/tex]

And replacing we got:

[tex] p =\frac{7}{51}= 0.1372[/tex]

And then the probability that is NOT from sport temas using the complement rule is given by:

[tex] q = 1-p =1- \frac{7}{51}= 0.8627[/tex]

And if we convert that into % we got:

[tex] 0.8627 *100= 86.27\%[/tex]

Approximately 86.27% of the floats were NOT sports teams

[tex] \purple \bold{a^2 - b^2} [/tex]

Step-by-step explanation:

X+4 is prime. X2-9can be factored using the [tex] \purple \bold{a^2 - b^2} [/tex] formula

[tex] x^2 - 9\\

=x^2 - 3^2 \\

= (x+3)(x-3)[/tex]

Answer: difference-of-squares

next one is (x+3)(x-3)(x+4)

Step-by-step explanation:

just took it on ed genuity :)

Answer:C

Step-by-step explanation:

Answer:

The answer is C

Step-by-step explanation:

Source: Dude trust me

Answer:

what she/he said

Step-by-step explanation:

Answer:

3

Step-by-step explanation:

27^1/3 = cuberoot(27) = 3

Answer:

X^4

------

 4

Step-by-step explanation:

The simplified expression is 1/4x²  

Polynomial is made up of two terms, namely Poly (meaning “many”) and Nominal (meaning “terms.”). A polynomial is an expression composed of variables, constants, and exponents, combined using mathematical operations such as addition, subtraction, multiplication, and division (No division operation by a variable). Based on the number of terms present in the expression, it is classified as monomial, binomial, and trinomial. For example P(x) = x²-5x+11

Given here, the expression is (20x⁻³ / 10x⁻¹)⁻² =2⁻²× x⁻²

                                                                             = 1/4x²

Hence, the simplified expression is  1/4x²

Learn more about polynomial expression here:

https://brainly.com/question/11536910

#SPJ2

Answer:

Predicted response value = 39.536

Note that this predicted response value will most likely be far from the actual response value because the correlation coefficient of the regression equation used (r = 0.39) is too far away from 1.

Step-by-step explanation:

The response variable is the dependent variable (y) whose value is obtained from the expression involving the independent variable (x).

For this question, although the correlation coefficient, r = 0.39, is far from 1, the regression equation is

y = 0.495x - 14.914

The predicted response value will be obtained from the explanatory variable and the regression equation

x = 110

y = 0.495x - 14.914

y = (0.495×110) - 14.914 = 39.536

Note that this predicted response value will most likely be far from the actual response value because the correlation coefficient of the regression equation used (r = 0.39) is too far away from 1.

Hope this Helps!!!

Answer:

No the slot machine doesn't appear to function as expected.

Step-by-step explanation:

From chi-squared table , for 9 degrees of freedom and alpha 0.05,

critical value is, 3.325.

Since observed value is greater than critical value we can say that actual outcomes do not agree with the expected frequencies. The slot machine doesn't appear to function as expected.

Answer:

Step-by-step explanation:

Hello!

I didn't find the exact box plot for this exercise but I've found one that'll help you identify the required values

When constructing a box plot the box lower and upper limits are defined by the first and third quartiles and the line separating it in two represents the median.

In this case, the box is lying on the side, the first quartile is represented by the left side of the box. If you see the graphic this one corresponds to 25.

The median, as said, is represented by the line drawn inside the box, it is not necessarily in its middle but it will always be inside it.

Watching the example, the median is 33

I hope this helps!

Answer: D

Step-by-step explanation:

Answer:

b = 4.6 ft

h = 2.3 ft

Step-by-step explanation:

The volume of the tank is given by:

[tex]b^2*h=49[/tex]

Where 'b' is the length of the each side of the square base, and 'h' is the height of the tank.

The surface area can be written as:

[tex]A=b^2+4bh\\A=b^2+4b*({\frac{49}{b^2}})\\A=b^2+\frac{196}{b}[/tex]

The value of b for which the derivate of the expression above is zero is the value that yields the minimum surface area:

[tex]\frac{dA}{db} =0=2b-\frac{196}{b^2}\\2b^3=196\\b=4.61\ ft[/tex]

The value of h is then:

[tex]h=\frac{49}{4.61^2}\\h=2.31\ ft[/tex]

Rounded to the nearest tenth, the dimensions are b = 4.6 ft and h = 2.3 ft.

Answer:

473 feet.

Step-by-step explanation:

Let's look at the image below. We have that the angle of elevation from Justin parking spot is 11º and the height of the building is 92 feet and we need to know how far from the building is Justin parked, in other words, we need to find x in the image.

We can see that to find x we can use a trigonometric function (in this case is tan since we have the Opposite side (92 feet) and we need the Adjacent side (x)

Thus we have:

[tex]Tan11= \frac{92}{x} \\0.1943=\frac{92}{x}\\ x=\frac{92}{0.1943}\\ x=473.49\\x=473[/tex]

Thus, Justin is parked 473 feet away from the center court.

Answer:

103

Step-by-step explanation:

A number to the power of a negative exponent, means 1 divided by that same number to the power of the positive exponent.

1/(216^(-2/3)) + 1/(256^(-3/4)) + 1/(243^(-1/5))

Break it apart into three pieces.

1/(216^(-2/3))

216^(2/3) = 36

1/(256^(-3/4))

256^(3/4) = 64

1/(243^(-1/5))

243^(1/5) = 3

So...

1/(216^(-2/3)) = 36

1/(256^(-3/4)) = 64

1/(243^(-1/5)) = 3

Add the numbers gives:

36 + 64 + 3 = 103

Answer:

about 3878 ft

Step-by-step explanation:

Assuming that the cable is not doubled, we need to find the length of the base of the mountain i.e

3400/tan(74)  = about 975 ft

Therefore, the length of the cable  =

√[ 3400² + (975 + 890)²]  = about 3878 ft

Answer:

ROA = 7.77 percent

Step-by-step explanation:

Borland, Inc., has a profit margin of 5.6 percent on sales of $13.6 million

Thus, profit = 5.6% of  $13.6 million

profit = 5.6 / 100 *  $13.6 million = $0.7616 million

Profit is same as net income

Formula for ROA (return on asset) = net income/ total asset

total asset as given = $9.8 million

Thus, ROA = $0.7616/ $9.8 = 0.0777

ROA in percentage = 0.0777*100 = 7.77

Thus, ROA is 7.77 percent .

Completed Question

Outputs to be matched to the functions are:

Answer:

Step-by-step explanation:

Given the vector x: x <- c(2, 43, 27, 96, 18)

Sort

In R, the sort(x)  function is used to arrange the entries in ascending or descending order. By default, R will sort the vector in ascending order.

Therefore, the output that matches the sort function is:

sort(x): 2, 18, 27, 43, 96

Rank

The rank function returns a vector with the "rank" of each value.

x <- c(2, 43, 27, 96, 18)

Therefore, the output of rank(x)  is: 1, 4, 3, 5, 2

Order

When the function is sorted, the order function gives the previous location of each of the element of the vector.

Using the sort(x) function, we obtain: 2, 18, 27, 43, 96

In the vector: x <- c(2, 43, 27, 96, 18)

Therefore, the output of order(x) is: 1, 5, 3, 2, 4

Answer:

Step-by-step explanation:

Inventory turn over is the same as the inventory turn over ratio. Inventory turn over is defined simply as the ratio of the cost of goods that was sold (net sales) to the average inventory at the selling price.

Inventory turn over = Cost of goods/average inventory

Cost of goods sold = $50000

Average inventory = beginning of inventory + ending inventory/2

Average inventory = $16000+$20000/2

Average inventory = $36000/2

Average inventory = $18000

Inventory turn over = $50000/$18000

Inventory turn over= 2.78

Answer: 5h/3

Step-by-step explanation:

12 hours passed, and 20 degrees dropped.

Every hour, that's 20/12 = 5/3 degrees dropped. Therefore, the equation is 5h/3.

Hope that helped,

-sirswagger21

Answer:

5h 3

Step-by-step explanation:

12 hours passed, and 20 degrees dropped.

Every hour, that's 20/12 = 5/3 degrees dropped. Therefore, the equation is 5h/3.

Hope that helped,

-sirswagger21

Answer:

So your question was not very clear but with (f+g) im guessing thats f(x)+g(x)

So first we add them x^2+4x-32   +   x-4 then we will get x^2 + 5x - 36

Then we need to multiply both

(x^2+5x-36)(x^2+5x-36)

=

(x^2+5x-36)^2

The only reason im not solving it out is because it yields large numbers and you might not understand.

Answer:

Step-by-step explanation:

Let x be the random variable representing the dollar value of unusual activity for a customer in a month. Since it is normally distributed and the population mean and population standard deviation are known, we would apply the formula,

z = (x - µ)/σ

Where

x = sample mean

µ = population mean

σ = standard deviation

From the information given,

µ = 250

σ = √variance = √2400 = 48.99

a) the probability of $250 to $294 in unusual activity in a month is expressed as

P(250 ≤ x ≤ 294)

For x = 250,

z = (250 - 250)/48.99 = 0

Looking at the normal distribution table, the probability corresponding to the z score is 0.5

For x = 294

z = (294 - 250)/48.99 = 0.9

Looking at the normal distribution table, the probability corresponding to the z score is 0.8159

Therefore,

P(250 ≤ x ≤ 294) = 0.8159 - 0.5 = 0.3159

b) the probability of more than $294 in unusual activity in a month is expressed as

P(x > 294) = 1 - P(x < 294)

P(x > 294) = 1 - 0.8159 = 0.1841

c) since n = 10, the formula becomes

z = (x - µ)/(σ/n)

z = (294 - 250)/(48.99/√10) = 2.84

Looking at the normal distribution table, the probability is 0.9977

Therefore, the probability that at least one of these customers exceeds $294 in unusual activity in a month is

1 - 0.9977 = 0.0023

Answer:

[tex]x^{6} y^{3}[/tex]

Step-by-step explanation:

[tex](x^2y)3[/tex]

[tex]x^{2 \times 3} \times y^3[/tex]

[tex]x^{6} \times y^3[/tex]

Answer: Jose should have the factory make 50 FS20 stereo tuners and 14 S100 stereo tuners each week to make the most profit

Step-by-step explanation:

Since each S100 takes 8 ounces of plastic and 4 ounces of metal. Each FS20 requires 4 ounces of plastic and 6 ounces of metal. And the factory has 312 ounces of plastic, 372 ounces of metal available, then,

For plastic

8 ounces + 4 ounces = 12 ounces

The number of stereo tuners it can produce will be

312/12 = 26 stereo tuners

For metal

4 ounces + 6 ounces = 10 ounces

The number of stereo tuners it can produce will be

372/10 = 37.2 = 37 approximately

Since FS20 generate more profit than S100, let assume that Jose produces 50 FS20 by consuming

4 × 50 = 200 ounces of plastic

6 × 50 = 300 ounces of metal

The remaining plastic will be

312 - 200 = 112

The remaining plastic will be

372 - 300 = 72

Divide 112 by 8 in order to make S100

112/8 = 14

Also 72/4 = 18.

Therefore, Jose should have the factory make 50 FS20 stereo tuners and 14 S100 stereo tuners each week to make the most profit

Answer:

SAS

Step-by-step explanation:

the angles are congruent, and the 2 pairs of sides are proportional.

200/150 is 4/3 and 320/240 is 4/3 as well.

therefore Side-Angle-Side

Answer:

-3

Step-by-step explanation: