Which rational function does this graph represent?

Answer:

he additive inverse of:

a)  [tex]-6x^2-x-2[/tex] is : [tex]6x^2+x+2[/tex]

b)  [tex]6x^2-x+2[/tex]  is :  [tex]-6x^2+x-2[/tex]

c)  [tex]6x^2+x-2[/tex]  is :  [tex]-6x^2-x+2[/tex]

d)  [tex]6x^2+x+2[/tex]  is :  [tex]-6x^2-x-2[/tex]

Step-by-step explanation:

You need to consider that the additive inverse of a polynomial is that polynomial that consists of the opposite of each term of the polynomial given.

Then, the additive inverse of:

a)  [tex]-6x^2-x-2[/tex] is :  [tex]6x^2+x+2[/tex]

b)  [tex]6x^2-x+2[/tex]  is :  [tex]-6x^2+x-2[/tex]

c)  [tex]6x^2+x-2[/tex]  is :  [tex]-6x^2-x+2[/tex]

d)  [tex]6x^2+x+2[/tex]  is :  [tex]-6x^2-x-2[/tex]

Answer:

Given,

X=2

y=-2

z=3

Now,

[tex]3x + y - z \\ = 3 \times 2 + ( - 2) - 3 \\ = 6 + ( - 2) - 3 \\ = 6 - 2 - 3 \\ = 4 - 3 \\ = 1[/tex]

Hope this helps...

Good luck on your assignment..

Answer:

1

Step-by-step explanation:

3X+Y-Z

Where X = 2, Y = -2 amd Z = 3

=> 3(2)+(-2)-(3)

=> 6-2-3

=> 4-3

=> 1

Answer:

3

Step-by-step explanation:

Given  

y

=

2

x

2

−

4

x

+

3

The y-intercept is the value of  

y

when  

x

=

0

XXX

y

=

2

(

0

)

2

−

4

(

0

)

+

3

=

3

For a quadratic in the general form:

XXX

y

=

a

x

2

+

b

x

+

c

the determinant  

Δ

=

b

2

−

4

a

c

indicates the number of zeros.

Δ

⎧

⎪

⎨

⎪

⎩

<

0

==⇒  

no solutions

=

0

==⇒  

one solution

>

0

==⇒  

two solutions

In this case

XXX

Δ

=

(

−

4

)

2

−

4

(

2

)

(

3

)

<

0

so there are no solutions (i.e. no values for which the expression is equal to zero).

This can also be seen from a graph of this equation:

graph{2x^2-4x+3 [-6.66, 13.34, -0.64, 9.36]}

Answer link

Vinícius Ferraz

Nov 13, 2015

(

0

,

3

)

Explanation:

x

=

0

⇒

y

=

0

−

0

+

3

y

=

0

⇒

x

=

−

b

±

√

b

2

−

4

a

c

2

a

a

=

2

,

b

=

−

4

,

c

=

3

But  

Δ

< 0, then there is no real root  

(

x

0

,

0

)

.

Answer:

it has 2

Step-by-step explanation:

I hope this helps!

Step-by-step explanation:

here,

31 cup of milk require 41 cup of water.

1 cup of milk require 41/31 cup of water.

so, 41/31 cup of water is required for 1 cup of milk.

hope u get it..

Answer:

Remote interior angle

Step-by-step explanation:

<Y is a remote (non-adjacent) interior angle for <w.

━━━━━━━☆☆━━━━━━━

▹ Answer

Remote Interior Angle

▹ Step-by-Step Explanation

∠Y is a non-adjacent interior angle for ∠W.

Hope this helps!

- CloutAnswers ❁

Brainliest is greatly appreciated!

━━━━━━━☆☆━━━━━━━

Answer:

0.65

Step-by-step explanation:

There are 65 student that do sports as 20+20+25=65. In total there are 100 student and you find this by adding up all the values. Now all you do is divide 65/100 and get 0.65 and that is the probability a random student plays sports.

Answer: P(t) = 1.25.sin([tex]\frac{\pi}{3}[/tex].t) + 5.65

Step-by-step explanation: A motion repeating itself in a fixed time period is a periodic motion and can be modeled by the functions:

y = A.sin(B.t - C) + D or y = Acos(B.t - C) + D

where:

A is amplitude A=|A|

B is related to the period by: T = [tex]\frac{2.\pi}{B}[/tex]

C is the phase shift or horizontal shift: [tex]\frac{C}{B}[/tex]

D is the vertical shift

In this question, the motion of Pluto is modeled by a sine function and doesn't have phase shift, C = 0.

Amplitude:

a = [tex]\frac{largest - smallest}{2}[/tex]

At t=0, Pluto is the farthest from the sun, a distance 6.9 billions km away. At t=66, it is closest to the star, P(66) = 4.4 billions km. Then:

a = [tex]\frac{6.9-4.4}{2}[/tex]

a = 1.25

b

A time period for Pluto is T=66 years:

66 = [tex]\frac{2.\pi}{b}[/tex]

b = [tex]\frac{\pi}{33}[/tex]

Vertical Shift

It can be calculated as:

d = [tex]\frac{largest+smallest}{2}[/tex]

d = [tex]\frac{6.9+4.4}{2}[/tex]

d = 5.65

Knowing a, b and d, substitute in the equivalent positions and find P(t).

P(t) = a.sin(b.t) + d

P(t) = 1.25.sin([tex]\frac{\pi}{3}[/tex].t) + 5.65

The Pluto's distance from the sun as a function of time is

P(t) = 1.25.sin([tex]\frac{\pi}{3}[/tex].t) + 5.65

Answer:

P(t) = 1.25.sin(.t) + 5.65

Step-by-step explanation:

Answer:

a) P(A∩B) = 0.29

b) P1 = 0.1

c) P = 0.35

Step-by-step explanation:

Let's call A the event that the motorist stop at the first signal, and B the event that the motorist stop at the second signal.

From the question we know:

P(A) = 0.39

P(B) = 0.54

P(A∪B) = 0.64

Where P(A∪B) is the probability that he stop in the first, the second or both signals. Additionally, P(A∪B) can be calculated as:

P(A∪B)  = P(A) + P(B) - P(A∩B)

Where P(A∩B) is the probability that he stops at both signals.

So, replacing the values and solving for P(A∩B), we get:

0.64 = 0.39 + 0.54 - P(A∩B)

P(A∩B) = 0.29

Then, the probability P1 that he just stop at the first signal can be calculated as:

P1 = P(A) - P(A∩B) = 0.39 - 0.29 = 0.1

At the same way, the probability P2 that he just stop at the second signal can be calculated as:

P2 = P(B) - P(A∩B) = 0.54 - 0.29 = 0.25

Finally, the probability P that he stops at exactly one signal is:

P = P1 + P2 = 0.1 + 0.25 = 0.35

Answer:

2049.

Step-by-step explanation:

2045 - 1983 = 62 years.

So the competition will take place in 1983 + 60 = 2043.

After 2045  the competition takes place in 2049.

Answer:

Let the number be x

The statement is written as

[tex] \frac{3}{7}x = \frac{29}{14} [/tex]

Multiply through by 14

That's

[tex] 14 \times \frac{3}{7} x = \frac{29}{14} \times 14[/tex]

We get

2 × 3x = 29

6x = 29

Divide both sides by 6

That's

[tex] \frac{6x}{6} = \frac{29}{6} [/tex]

[tex]x \: = \frac{29}{6} \: \: or \\ 4 \frac{5}{6} [/tex]

Hope this helps you

Answer:

Option (3)

Step-by-step explanation:

Given question is incomplete; here is the complete question.

The function f(x) = –x2 – 4x + 5 is shown on the graph. Which statement about the function is true?

The domain of the function is all real numbers less than or equal to −2.

The domain of the function is all real numbers less than or equal to 9.

The range of the function is all real numbers less than or equal to −2.

The range of the function is all real numbers less than or equal to 9

By using a graph tool we get a parabola opening downwards.

Since domain of a function is represented by x-values and range by y-values.

Domain of the given function will be (-∞, ∞)

Range of the function will be (-∞, 9] Or a set of all real numbers less thn equal to 9.

Therefore, Option (3) will be the answer.

Answer:

First one is (x+2.4)

Second one is 4(x+2.4)=14.8

Step-by-step explanation:

Answer:

What expression would represent how far Bijan runs everyday?

✔ (x + 2.4)

What is the equation that represents his total distance after 4 days?

✔ 4(x + 2.4) = 14.8

Step-by-step explanation: I TOOK THE TEST

Answer:

CI: {0.4085; 0.6647}

Step-by-step explanation:

The confidence interval for a proportion (p) is given by:

[tex]p \pm z*\sqrt{\frac{(1-p)*p}{n} }[/tex]

Where n is the sample size, and z is the z-score for the desired confidence interval. The score for a 90% confidence interval is 1.645. The proportion of depositors who ask for cash back is:

[tex]p=\frac{22}{41}=0.536585[/tex]

Thus the confidence interval is:

[tex]0.536585 \pm 1.645*\sqrt{\frac{(1-0.536585)*0.536585}{41}}\\0.536585 \pm 0.128109\\L=0.4085\\U=0.6647[/tex]

The confidence interval for the proportion of all depositors who ask for cash back is CI: {0.4085; 0.6647}

Answer:

(190-5a)°

Step-by-step explanation:

Sum of internal angles of a triangle equals to 180°

If the third angle is x, then we have:

The third angle is: (190-5a)°

Answer:

6*2 = 12

Step-by-step explanation:

2 + 2 + 2 + 2 + 2 + 2 = 12

There are six 2's being added together

6*2 = 12

Answer: 2*6

Step-by-step explanation:

There are 6 2's shown in the question.  Thus, simply do 6*2.

Hope it helps <3

Answer:

so

slope is calculated this way:

[tex] \frac{3 - 6}{2 - 1} = \frac{ - 3}{1} = - 3[/tex]

let's calculate y init by:

3 = -3×2 + b

b = 9

so equation is:

y=-3x+9

Answer:

c = 6.25

Step-by-step explanation:

We are given the following piecewise function:

[tex]\left \{ {{cx^{2} + 2x, x < 3} \atop {3x^{3} - cx, x \geq 3}} \right[/tex]

Continuous function:

A function f(x) is continuous, at a point a, if:

[tex]\lim_{x \to a} f(x)[/tex] exists and [tex]\lim_{x \to a} f(x) = f(a)[/tex]

In this question:

Piece-wise function, so we have to verify if the limit exists.

The function changes at x = 3. So we verify at a = 3.

It will exist if:

[tex]\lim_{x \to 3^{-}} f(x) = \lim_{x \to 3^{+}} f(x)[/tex]

To the left:

Less than 3.

[tex]\lim_{x \to 3^{-}} f(x) = \lim_{x \to 3^{-}} cx^{2} + 2x = c*(3)^{2} + 2*3 = 9c + 6[/tex]

To the right:

Greater than 3.

[tex]\lim_{x \to 3^{+}} f(x) = \lim_{x \to 3^{+}} 3x^{3} - cx = 3*3^{3} - 3c = 81 - 3c[/tex]

f continuous:

They have to be equal:

[tex]\lim_{x \to 3^{-}} f(x) = \lim_{x \to 3^{+}} f(x)[/tex]

[tex]9c + 6 = 81 - 3c[/tex]

[tex]12c = 75[/tex]

[tex]c = \frac{75}{12}[/tex]

[tex]c = 6.25[/tex]

Answer:

Step-by-step explanation:

Probability is the likelihood or chance that an event will occur.

Probability = expected outcome/total outcome

Since a six-sided die is rolled, the total outcome will be the total number of possible siedes a die contain {1, 2, 3, 4, 5, 6} i.e 6 elements

If a number less than 2 is gotten, the expected outcome will be {1} i.e 1 element.

Probability of getting a number less than 2 = 1/6

If a prime number is gotten, the outcome will be the elements {2, 3, 5} i.e 3 elements.

The probability of getting a prime number = 3/6 = 1/2

The probability of getting a number less than 2 OR a prime number upon rolling a six-sided die will be 1/6*1/2 = 1/18

Answer:

Step-by-step explanation:

On a six-sided die, there is only one way to get a number less than 2, which is by rolling a 1.  So the probability of getting a number less than 2 is:

P left parenthesis l e s s space t h a n space 2 right parenthesis equals 1 over 6

There are three primes numbers when rolling a six-sided die, which are {2, 3, 5}.  So the probability of getting a prime number is:

P left parenthesis p r i m e right parenthesis equals 3 over 6

Since there is no overlap between these two events, the probability of getting a number less than 2 OR a prime number is:

P left parenthesis l e s s space t h a n space 2 space o r space p r i m e right parenthesis equals P left parenthesis l e s s space t h a n space 2 right parenthesis plus P left parenthesis p r i m e right parenthesis equals 1 over 6 plus 3 over 6 equals 4 over 6 equals 2 over 3

Answer is 2/3

Hey there! :)

Answer:

Last option. (-1, 0) and (0, 6).

Step-by-step explanation:

Solve this system by setting the two equations equal to each other:

6x + 6 = -x² + 5x + 6

Rearrange the equation:

x² + 6x + 6 - 5x - 6 = 0

Combine like terms:

x² + x = 0

Factor out x:

x(x + 1) = 0

Set each factor equal to 0:

x = 0

x + 1 = 0

x = -1

These are the x values of the solutions. Plug these into an equation to solve for y:

y = 6(0) + 6

y = 6

-------

y = 6(-1) + 6

y = -6 + 6

y = 0

Therefore, the solutions to the equation are (-1, 0) and (0, 6).

Answer:

B. -1.

Step-by-step explanation:

[tex]i^1[/tex] = i

[tex]i^2 = -1[/tex]

[tex]i^3 = -i[/tex]

[tex]i^4 = 1[/tex]

...And it keeps going in a pattern, from i to -1 to -i to 1. And so, we have four values.

34 / 4 = 8 with a remainder of 2. That means that the value of [tex]i^{34}[/tex] is the same thing as [tex]i^2\\[/tex], so it is B. -1.

Hope this helps!

Answer:

940.8 N

1254.4 N

Step-by-step explanation:

I would think the questions would be to calculate the forces at the top of the cube and at the sides. Thus:

On the top:

F = pressure * area

P = density * gravity * height

the height would be:

1m - 0.4m = 0.6m

replacing:

P = 1000 * 9.8 * 0.6 = 5880

A = (0.4) ^ 2 = 0.16

F = 5880 * 0.16

F = 940.8 N

On the sides:

dF = d * g * h * dA

dA = 0.4 * dh replacing

dF = 1000 * 9.8 * h * 0.4 * dh

dF = 3920 * h * dh

We integrate both sides and we have:

F = 3920 * (h ^ 2/2), h = 0.6 up to h = 1

F = (3920/2) * (1 ^ 2 - 0.6 ^ 2)

F = 1254.4 N

Answer:

a

The Null hypothesis represented as

     [tex]H_0: \mu_1 - \mu_2 = 0[/tex]

The Alternative hypothesis represented as

     [tex]H_a: \mu_1 - \mu_2 < 0[/tex]

b

p-value =  P(Z <  -3.37  )  = 0.000376

c

There is insufficient evidence to conclude that graduate students score higher, on average, on the HPI than undergraduate students

Step-by-step explanation:

From the question we are told that

   The population size is  [tex]n= 650[/tex]

    The  sample size for graduates is  [tex]n_1 = 300[/tex]

     The sample  mean for graduates is [tex]\= x _1 = 148[/tex]

      The sample  standard deviation for graduates is [tex]\sigma_1 = 16[/tex]

    The  sample size for under-graduates is [tex]n _2 = 350[/tex]

         The sample  mean for under-graduates is [tex]\= x _2 = 153[/tex]

         The sample  standard deviation for graduates is [tex]\sigma_2 = 21[/tex]

The Null hypothesis represented as

     [tex]H_0: \mu_1 - \mu_2 = 0[/tex]

The Alternative hypothesis represented as

     [tex]H_a: \mu_1 - \mu_2 < 0[/tex]

Where [tex]\mu_1 \ and \ \mu_2[/tex] are the population mean

  Now the test statistic is mathematically represented as

          [tex]t = \frac{(\= x_1 - \= x_2 ) }{ \sqrt{ \frac{ (n_1 - 1 )\sigma_1 ^2 + (n_2 - 1)\sigma_2^2}{n_1 +n_2 -2} } * \sqrt{ \frac{1}{n_1} + \frac{1}{n_2} } }[/tex]

substituting values

       [tex]t = \frac{(148 - 153 ) }{ \sqrt{ \frac{ (300- 1 )16 ^2 + (350 - 1) 21^2}{300 +350 -2} } * \sqrt{ \frac{1}{300} + \frac{1}{350} } }[/tex]

      [tex]t = -3.37[/tex]

The p-values is mathematically evaluated as

     p-value =  P(Z <  -3.37  )  = 0.000376

The above answer is gotten using a p-value calculator  at (0.05) level of significance

     Looking the p-value we see that it is less than the level of significance (0.05)  so Null hypothesis is rejected

Hence there is insufficient evidence to conclude that graduate students score higher, on average, on the HPI than undergraduate students

Following are the two-Sample of the T-Test and CI:

[tex]\boxed{\boxed{\begin{matrix}Sample& N &Mean& StDev& SEMean\\ 1 &350 &153.0& 21.0 &1.1 \\ 2& 300& 148.0& 16.0& 0.92\end{matrix}}}[/tex]

Calculating the difference:

[tex]= \mu (1) - \mu (2)\\\\[/tex]

The estimated difference: [tex]5.00[/tex]

When the [tex]95\%[/tex] of CI so, the difference:[tex](2.09, 7.91)[/tex]

Therefore the T-Test difference value = 0

[tex]\to (vs \neq): T-Value = 3.37 \\\\\to P-Value = 0.001 \\\\\to DF = 648[/tex]

When the both use Pooled so, the StDev = 18.8583

Therefore, the final value of t is "3.37".

Learn more:

brainly.com/question/16380581

Answer:

a) 21.58% probability that exactly 3 people are repeat offenders

b) 97.91% probability that at least one person is a repeat offender

c) 3.69

d) 1.83

Step-by-step explanation:

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 expected value of the binomial distribution is:

[tex]E(X) = np[/tex]

The standard deviation of the binomial distribution is:

[tex]\sqrt{V(X)} = \sqrt{np(1-p)}[/tex]

9% of all drivers arrested for DUI (Driving Under the Influence) are repeat offenders

This means that [tex]p = 0.09[/tex]

41 people arrested for DUI in Illinois are selected at random.

This means that [tex]n = 41[/tex]

a. What is the probability that exactly 3 people are repeat offenders?

This is P(X = 3).

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

[tex]P(X = 3) = C_{41,3}.(0.09)^{3}.(0.91)^{38} = 0.2158[/tex]

21.58% probability that exactly 3 people are repeat offenders

b. What is the probability that at least one person is a repeat offender?

Either none are repeat offenders, or at least one is. The sum of the probabilities of these outcomes is 1. So

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

We want [tex]P(X \geq 1)[/tex].

Then

[tex]P(X \geq 1) = 1 - P(X = 0)[/tex]

In which

[tex]P(X = 0) = C_{41,0}.(0.09)^{0}.(0.91)^{41} = 0.0209[/tex]

[tex]P(X \geq 1) = 1 - P(X = 0) = 1 - 0.0209 = 0.9791[/tex]

97.91% probability that at least one person is a repeat offender

c. What is the mean number of repeat offenders?

[tex]E(X) = np = 41*0.09 = 3.69[/tex]

d. What is the standard deviation of the number of repeat offenders?

[tex]\sqrt{V(X)} = \sqrt{np(1-p)} = \sqrt{41*0.09*0.91} = 1.83[/tex]

Answer:

Domain : (-∞, ∞)

Range : (-∞, ∞)

Step-by-step explanation:

Parent function (y = [tex]\sqrt[3]{x}[/tex] ) of the given function y = -[tex]\sqrt[3]{x}[/tex] has been shown as the dotted line on the graph.

Solid curve represents the function,

y = [tex]-\sqrt[3]{x}[/tex]

Therefore, Domain of this function will be (-∞, ∞) Or x ∈ set of all real numbers.

And Range of the function will be (-∞, ∞) Or y ∈ set of all real numbers

Answer:

area = 36 ft²

Step-by-step explanation:

no figure has been given ..

therefore,  area of a triangle = 1/2 * b * h

assume b = 6 ft

assume h = 12 ft

area = 1/2 * 6 * 12

area = 36 ft²

Answer:

The common difference is 1/2

Step-by-step explanation:

Data obtained from the question include:

3rd term (a3) = 0

Common difference (d) =.?

From the question given, we were told that the 7th term (a7) and the 4th term (a4) are related by the following equation:

a7 – 2a4 = 1

Recall:

a7 = a + 6d

a4 = a + 3d

a3 = a + 2d

Note: 'a' is the first term, 'd' is the common difference. a3, a4 and a7 are the 3rd, 4th and 7th term respectively.

But, a3 = 0

a3 = a + 2d

0 = a + 2d

Rearrange

a = – 2d

Now:

a7 – 2a4 = 1

Substituting the value of a7 and a4, we have

a + 6d – 2(a + 3d) = 1

Sustitute the value of 'a' i.e –2d into the above equation, we have:

–2d + 6d – 2(–2d + 3d) = 1

4d –2(d) = 1

4d –2d = 1

2d = 1

Divide both side by 2

d = 1/2

Therefore, the common difference is 1/2

***Check:

d = 1/2

a = –2d = –2 x 1/2 = –1

a3 = 0

a3 = a + 2d

0 = –1 + 2(1/2)

0 = –1 + 1

0 = 0

a7 = a + 6d = –1 + 6(1/2) = –1 + 3 = 2

a4 = a + 3d = –1 + 3(1/2) = –1 + 3/2

= (–2 + 3)/2 = 1/2

a7 – 2a4 = 1

2 – 2(1/2 = 1

2 – 1 = 1

1 = 1

Answer: C - 600cm^2

Step-by-step explanation:

Area of one triangle:

(12)(5) ÷ 2 = 30

Area of two triangles:

30 x 2 = 60

Area of top rectangle:

Step 1: Figure out side length of triangle by using pythagorean:

√a^2 + b^2 =  c

√(5)^2 + (12)^2 =  c

√25 + 144 = c

√ 169 = c

13 = c

Step 2: Find area of top rectangle:

(18) x (13)

234

Find area of bottom rectangle:

(18) x (12)

216

Find area of back rectangle:

(18) x (5)

90

Add all the underlined numbers:

Area of two triangles + Area of top rectangle + Area of bottom rectangle + Area of back rectangle

60 + 234 + 216 + 90 = 600cm^2

Answers:

A ' = (-2, -3)

B ' = (0, -3)

C ' = (-1, 1)

=======================================================

Explanation:

To apply an x axis reflection, we simply change the sign of the y coordinate from positive to negative, or vice versa. The x coordinate stays as is.

Algebraically, the reflection rule used can be written as [tex](x,y) \to (x,-y)[/tex]

Applying this rule to the three given points will mean....

The diagram is provided below.

Side note: Any points on the x axis will stay where they are. That isn't the case here, but its for any future problem where it may come up. This only applies to x axis reflections.

Answer:

(-2,-3)...(0,-3)...(-1,1)

Step-by-step explanation:

Answer:

if you would travel 50km/h then the time will be 2.4hours

Step-by-step explanation:

speed=v1=60km/h

time=t1=2h

speed=v2=50km/h

time=t2=?

as we know that

v1×t1=v2×t2

evaluating the expression

(v1×t1)/v2=t2

putting values

[tex]\frac{60km/h*2h}{50km/h}=t2[/tex]

[tex]\frac{120km/h^2}{50km/h}=t2[/tex]

2.4hours=t2

i hope this will help you :)

Answer:

A 90% confidence interval for the mean weight is [21.78 ounces, 21.98 ounces].

Step-by-step explanation:

We are given the weights, in the ounces, of a sample of 12 boxes below;

Weights (X): 21.88, 21.76, 22.14, 21.63, 21.81, 22.12, 21.97, 21.57, 21.75, 21.96, 22.20, 21.80.

Firstly, the pivotal quantity for finding the confidence interval for the population mean is given by;

                         P.Q.  =  [tex]\frac{\bar X-\mu}{\frac{s}{\sqrt{n} } }[/tex]  ~ [tex]t_n_-_1[/tex]

where, [tex]\bar X[/tex] = sample mean weight = [tex]\frac{\sum X}{n}[/tex] = 21.88 ounces

            s = sample standard deviation = [tex]\sqrt{\frac{\sum (X-\bar X)^{2} }{n-1} }[/tex]  = 0.201 ounces

            n = sample of boxes = 12

            [tex]\mu[/tex] = population mean weight

Here for constructing a 90% confidence interval we have used a One-sample t-test statistics because we don't know about population standard deviation.

So, 90% confidence interval for the population mean, [tex]\mu[/tex] is ;

P(-1.796 < [tex]t_1_1[/tex] < 1.796) = 0.90  {As the critical value of t at 11 degrees of

                                                  freedom are -1.796 & 1.796 with P = 5%}  

P(-1.796 < [tex]\frac{\bar X-\mu}{\frac{s}{\sqrt{n} } }[/tex] < 1.796) = 0.90

P( [tex]-1.796 \times {\frac{s}{\sqrt{n} } }[/tex] < [tex]{\bar X-\mu}[/tex] < [tex]1.796 \times {\frac{s}{\sqrt{n} } }[/tex] ) = 0.90

P( [tex]\bar X-1.796 \times {\frac{s}{\sqrt{n} } }[/tex] < [tex]\mu[/tex] < [tex]\bar X+1.796 \times {\frac{s}{\sqrt{n} } }[/tex] ) = 0.90

90% confidence interval for [tex]\mu[/tex] = [ [tex]\bar X-1.796 \times {\frac{s}{\sqrt{n} } }[/tex] , [tex]\bar X+1.796 \times {\frac{s}{\sqrt{n} } }[/tex] ]

                                        = [ [tex]21.88-1.796 \times {\frac{0.201}{\sqrt{12} } }[/tex] , [tex]21.88+1.796 \times {\frac{0.201}{\sqrt{12} } }[/tex] ]

                                        = [21.78, 21.98]

Therefore, a 90% confidence interval for the mean weight is [21.78 ounces, 21.98 ounces].