Problem: According www.textrequest, an American between 18-24 sends and receives about 128 text messages per day. Assume that the population standard deviation is 30 for this age group. To get an idea about the true population mean you take a survey of 100 adults in that age group and find that their average is 135. Create a 90% confidence interval for the population average for this age group.

Answers

Answer 1

Answer:

(130.08, 139.92)

Step-by-step explanation:

Given that:

Mean (m) = 135

Standard deviation (σ) = 30

Sample size (n) = 100

α = 90%

The confidence interval value is obtained using the relation:

Mean ± Zcritical * (standard deviation / sqrt(n))

Zcritical at 90% = 1.64

standard deviation / sqrt(n) = 30 / sqrt(100)

= 30 / 10 = 3

Hence,

135 ± 1.64 * (3)

Lower limit : 135 - (1.64 * 3) = 130.08

Upper limit : 135 + (1.64 * 3) = 139.92

Hence,

Confidence interval = (130.08, 139.92)


Related Questions

Can someone help please

Answers

Answer:sorry i cant

Step-by-step explanation:

A cylindrical soup can has a radius of 8.4 cm and a height of 13.2 cm. What is the volume of the soup can to the nearest tenth of a cubic centimeter?
A= 110.9 cm3
B= 348.3 cm3
C= 673.8 cm3
D= 2926.1 cm3

Answers

Answer:

D. 2926.1 cm3

Step-by-step explanation:

To calculate volume of a cylinder, you need to use the equation V = pi r² h, where r is radius and h is height.

you have the right numbers to plug in, so pi times 8.4² times 13.2, which gives you 2926.05 which you round up to 2926.1 cm³

simplify x^2 + ax - 2a^2÷
3a^2 - 2ax - x^2?

Answers

Answer:

[tex] - \frac{x + 2a}{3a + x} [/tex]

Step-by-step explanation:

[tex] \frac{ {x + ax - 2 {a}}^{2} }{3a {}^{2} - 2ax - {x}^{2} } [/tex]

i) write ax as a difference

[tex] \frac{ {x}^{2} + 2ax - ax - 2 {a}^{2} }{3 {a}^{2} - 2ax - x {}^{2} } [/tex]

ii) write -2ax as a difference

[tex] \frac{ {x}^{2} + 2ax - ax - 2a {}^{2} }{3a {}^{2} + ax - 3ax - x {}^{2} } [/tex]

iii) factor out x from the expression

[tex] \frac{x(x + 2a) - ax - 2 {a}^{2} }{3 {a}^{2} + ax - 3ax - {x}^{2} } [/tex]

iv) factor out -a from the expression

[tex] \frac{x(x + 2a) - a(x + 2a)}{3 {a}^{2} + ax - 3ax - {x}^{2} } [/tex]

v) factor out a from the expression

[tex] \frac{x(x + 2a) - a(x + 2a)}{a(3a + x) - 3ax - {x}^{2} } [/tex]

vi) factor out -x from the expression

[tex] \frac{x(x + 2a) - a(x + 2a)}{a(3a + x) - x(3a + x)} [/tex]

vii) factor out x+2a from the expression

[tex] \frac{(x + 2a)(x - a)}{a(3a + x) - x(3a + x)} [/tex]

viii) factor out 3a+x from the expression

[tex] \frac{(x + 2a)(x - a)}{(3a + x)(a - x)} [/tex]

ix) factor out the negative sign from the expression and rearrange the term

[tex] \frac{(x + 2a)( - ( - a - x))}{(3a + x)(a - x)} [/tex]

x) reduce the fraction a-x

[tex] \frac{(x + 2a)( - 1)}{(3a + x)} [/tex]

[tex] - \frac{x + 2a}{3a + x} [/tex]

How many solutions does this equation have?
-3n = -4n + 7

Answers

Answer:

just one: 7 you isolate the numbers by doing -3n + 4n = 7, and u get n = 7

Answer:

2

Step-by-step explanation:

my soulstinos were Solution 1)

3

n

+

7

=

1

3

n

+

7

7

=

1

7

3

n

+

0

=

8

3

n

=

8

3

n

3

=

8

3

3

n

3

=

8

3

n

=

8

3

Solution 2)

3

n

+

7

=

1

3

n

+

7

7

=

1

7

3

n

+

0

=

6

3

n

=

6

3

n

3

=

6

3

3

n

3

=

2

n

=

2

The solution is:

n

=

8

3

and

n

=

2

Multiply (6.5 x 10)(1 x 10). Express the result in scientific notation.

Answers

Answer:

ans=6.5×10²

Step-by-step explanation:

ans =650=6.5×10²

∠A and ∠ B ∠B are complementary angles. If m ∠ A = ( 2 x + 10 ) ∘ ∠A=(2x+10) ∘ and m ∠ B = ( 3 x + 15 ) ∘ ∠B=(3x+15) ∘ , then find the measure of ∠ B ∠B

Answers

Answer:

you are in my class I need this too

what is 457 times 3792 divided by 382 + 39281.028

Answers

Answer: 43817.5306178

Step-by-step explanation:

Find the area of the shaded regions below. Give your answer as a completely simplified exact value in terms of pi (no approximations).

Answers

Answer:

area = 4π-8 cm²

Which function has a graph with a positive y-intercept?
A. I and III only
B. I only
C. II, and III
D. III only

Answers

Answer:are you taking AP calculus AB

Step-by-step explanation:

Answer:

A l and lll

my teacher helped me

HELP WHATS THE ANSWER

Answers

Answer:

The answer is 0, hope this helps

which of the following does the extrema represent
A. A turning point of the function

B. The minimum value of a function

C. Either a maximum or a minimum value of a function

D. The maximum value of a function​

Answers

Answer:

A

Step-by-step explanation:

Someone help me with this, please! i’ll mark u as brainlist

Answers

Answer:

x = 8

Step-by-step explanation:

2x + 5 = 21

      -5    -5

      2x = 16

     2x/2 = 16/2 ( divided 2 on both sides)

     you get x= 8

to check your work, replace x with 8 in the equation

                            2 x 8 + 5 = 21    ( don't forget PEMDAS!!)

                               16 + 5 = 21  

Solve the inequality.

p + 14 ≥ 2

Answers

Answer:

p [tex]\geq[/tex] -12

Step-by-step explanation:

Subtract 14

p [tex]\geq[/tex] -12

The solution to the inequality from the information given is p ≥ -12

What is inequality?

Inequality shows the relationship between two expressions and this relationship is identified by using the inequality signs (<, >, ≤, ≥).

The solution to the inequality p + 14 ≥ 2 can be determined by having the variables on one side and the numbers on the other side. To do that:

Let us subtract 14 from both sides of the equation we have:

p + 14 - 14 ≥ 2 - 14

p ≥ -12

Learn more about inequality here:

https://brainly.com/question/24372553

#SPJ2

What is long division answer to 6 divided by 92

Answers

The answer is 0.065217391304348

What does x, and y equal

Answers

Answer:

x = 1.25

y = 1.75

Step-by-step explanation:

Since, the line that is 8 units long is parallel to the line that is ten units long.

Therefore, both the triangles are similar by AA postulate.

Corresponding sides of of the similar triangles are in proportion.

Therefore,

[tex] \frac{5}{x + 5} = \frac{7}{y + 7} = \frac{8}{10} \\ \\ \implies \frac{5}{x + 5} = \frac{8}{10} \\ \\ 5 \times 10 = 8(x + 5) \\ \\ 50 = 8x + 40 \\ \\ 50 - 40 = 8x \\ \\ 10 = 8x \\ \\ \frac{10}{8} = x \\ \\ x = 1.25 \\ \\ \\ \frac{7}{y + 7} = \frac{8}{10} \\ \\ 7 \times 10 = 8(y + 7) \\ \\ 70 = 8y + 56 \\ \\ 70 - 56 = 8y \\ \\ 14 = 8y \\ \\ \frac{14}{8} = y \\ \\ y = 1.75[/tex]

Round 4,368 to the nearest ten

Answers

Answer:

4,370

Step-by-step explanation:

If you are looking for the nearest ten in 4,368, you round up the number 8. Eight is greater than five and not less than four, therefore, the answer is 4,370. Good Luck on whatever assignment you're doing!

Answer:
4370

Explanation:
5 or more you round to the next number. In this case 8 is above 5 so you round to the next number of 68 which is 70

can u pls help me with this question ​

Answers

The answer is 4 miles and hour because at the x it is the amount of hours and 4 y falls on the line above it

Simplify expression (distributive property) 11(9+d) if correct I'll mark brainliest!

Answers

11 x 9 is 99 so then you do 11 x d and that’s 11d so it would be 99+11d :)

Answer After Distributing: 99 + 11d

Work: You multiply 9 and d by 11, and you get 99 + 11d.

I hope this helps, and Happy Holidays! :)

What is the vertex of the following: y=1/4x^2+2x+6

Answers

Answer:

Yea i definitly just lost brain cells

Step-by-step explanation:

Q.23 Prove that: (sin4A - cos4A + 1) = 2sin2A

Answers

Answer:

Step-by-step explanation:

I think you have the question incomplete, and that this is the complete question

sin^4a + cos^4a = 1 - 2sin^2a.cos^2a

To do this, we can start my mirroring the equation.

x² + y² = (x + y)² - 2xy,

This helps us break down the power from 4 to 2, so that we have

(sin²a)² + (cos²a)² = (sin²a + cos²a) ² - 2(sin²a) (cos²a)

Recall from identity that

Sin²Φ + cos²Φ = 1, so therefore

(sin²a)² + (cos²a)² = 1² - 2(sin²a) (cos²a)

On expanding the power and the brackets, we find that we have the equation proved.

sin^4a + cos^4a = 1 - 2sin^2a.cos^2a

A worker at a snack stand opened a new box of cups. On the first day, the worker used 30 cups from the box. On the second day, the worker used 15% of the remaining cups in the box. A total of 90 cups were used on the second day. What was the original number of cups in the box before any cups were used?

Answers

Answer:

630 cups

Step-by-step explanation:

Percentages

This problem is most easily solved backward, i.e., from the final data up to the beginning.

There was a new box of cups and the worker at a snack stand opened it. He first used 30 cups from the box and the second day he uses 15% of the remaining cups in the box, and we are told that represents 90 cups.

If 15% (0.15) equals 90 cups, then the number of cups before the second day was 90/0.15 = 600 cups.

On the first day, we used 30 cups, thus the original number of cups in the box was 600+30=630 cups

Estimate the coordinates of the point where the two lines meet.


Choose two equations that make up the system represented by the graph.

y=54x

y=6−2.5x

y=2.5x+6

y=6−3x

y=0.8x

Answers

Answer:
y = 6 - 2.5x
y = 0.8x

The baker pays $0.60 per pound for sugar and $1.35 per pound for butter. Which expression shows how much the baker will spend
if he buys 4 pounds of butter and 10 pounds of sugar?

Answers

Answer: $6 for sugar and $5.40 for butter
Explanation: You need to multiply the amount it costs by the amount needed and you get the answers.
$0.60 x 10 = $6.00
$1.35 x 4 = $5.40

Aaliyah is working two summer jobs, making $7 per hour walking dogs and making $10 per hour tutoring. In a given week, she can work no more than 17 total hours and must earn no less than $140. Also, she must work at least 2 hours walking dogs and at most 13 hours tutoring. If xx represents the number of hours walking dogs and yy represents the number of hours tutoring, write and solve a system of inequalities graphically and determine one possible solution.

Answers

Answer:

140 >/ 7x + 10y (read as 140 is greater than or equal to 7x plus 10y)

x + y /< 17 - to represent the number of hours she can work

she will work at least 10 hours walking dogs and at least 7 tutoring

Step-by-step explanation:

Which statement is true about points located in quadrant Ill in the coordinate
plane?
O A. The x-coordinate is negative, and the y-coordinate is positive.
B. The x-coordinate is positive, and the y-coordinate is negative.
C. The x-coordinate is negative, and the y-coordinate is negative,
D. The x-coordinate is positive, and the y-coordinate is positive.
Please answer TODAY DEC 15
I WILL GIVE 100 POINTS TO THE FIRST PERSON THAT ANSWERS

Answers

I think the answer is the option B:))))

Answer: C

Step-by-step explanation

I Think Its C

Camilla has already baked five pies and she can make one pie with additional cup of sugar she buys how many additional cups of sugar does Camila need in order to bake a total of 49 pies

Answers

I used to know a Camilla, she cheated on me for my brother...pain

Rain minus the \

there are 7209 students at a amusement park. to the nearest thousands, how many students are in the park

Answers

Step-by-step explanation:

In ordee to round the number 7209 to the nearest thousands, we take a look at the digit in the hundreds place (which is 2).

Since 2 < 5, we round the number itself down to the nearest thousands:

7209 => 7000.

Hence our rounded number is 7000.

Answer:

7000

Step-by-step explanation:

The thousandths place in 7209 is less than 5, the number will change to 7000.

Please can someone help me please
It is attached

Answers

the answer is 1! I hope this is right
Simplify the expression

(y+1)^3

Using , (a+b)^3=a^3a^2b+3ab^2+b^3expand the expression

y^3+3y^2+3y+1=
Answer

helpp hurrryyyyyyyyyy​

Answers

Answer:

N=10

Step-by-step explanation:

Write the equation for the graph below. Points (-5,1) (-4,2) (-1,3)

Answers

Answer:

Concept: Derivation of Equations

Let us find the parent graph We can tell that the equation of the parent graph is [tex] \sqrt{x} [/tex]Hence we perform a transformation moving five units to the left and one unit upSo out result equation is [tex] \sqrt{x + 5} + 1[/tex]General note, if you move to the left its positive, if you move to the right its negative.If you move upwards its positive and downwards its negative.Give brainlist
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