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

Which of the
the
following fractions is the largest
11/16 , 3/5 , 7/10 , 13/18

Answers

Answer:

11/16, 3/5, 7/10

Step-by-step explanation:

The mean running time of a certain variety of nickel-cadmium rechargeable flashlight battery is known to be normally distributed with a mean of 8.5. A change in production method for this battery has been proposed, and a simple random sample of 64 batteries produced by the new method has mean running time of 8.72 hours. Assume the population is normally distributed with a standard deviation of 0.55 hour as known and remains unchanged, test a claim that the new production method improving the battery mean running time using 0.05 significance level.

Answers

Answer:

answer is a

Step-by-step explanation:

Express 0.2 as a fraction.

Answers

Answer:

1/5

Step-by-step explanation:

0.2 = 2/10

2/10 = 1/5

Answer:

0.2 = 1/5

Step-by-step explanation:

0.2

=  

0.2 × 10

=  

2/10

=  

2 ÷ 2

10 ÷ 2

=  

1/5

1 1/2 x 4 1/4 = ?
PLZ ANSWER QUICKLY

Answers

451/8=56.38 is what i got

Express as a fraction or a mixed number
1 1/2%

Answers

Answer:

5 and 1/2

Step-by-step explanation:

given the side lengths of 6, 13, and 20, determine whether the triangle is acute , right , obtuse, or not a triangle.

Answers

Answer:

Not a triangle.

Step-by-step explanation:

Sum of the two smaller sides must be greater than the largest side.

PLEASE HELP RN! 50 POINTS IF YOU ANSWER THIS IS DUE TODAY

Answers

Answer:

I graphed this...

Step-by-step explanation:

It is not linear because it is not a strait line and it doesnt go through the middle!

Hope this helps! :)

Can someone help me with these 2 questions real quick?

Answers

Answer:

<M = 32 and <Y = 103

Step-by-step explanation:

1. Since triangle BCM is congruent to triangle ZYR, we know the corresponding parts of the triangles are congruent. Therefore, <Z = <B = 45. The sum of a triangle’s angles is 180, so <M = 180 - <B - <C = 180 - 45 - 103 = 32

2. This is the exact same diagram, so we can use the information we have collected in #1. Since corresponding parts of congruent triangles are congruent, <Y must be congruent to <C, which equals 103. Therefore, <Y = 103.

I hope this helps! :)

1 should be 45 degrees
2 should be 103 degrees

mark me brainliest if the answer is correct, thank you in advance :)

Find the smallest positive four-digit number that is divisible by each of the four smallest prime numbers.

Answers

Answer:

It might be 1,050. Also can't believe thats a college question-

It was very easy to solve! Help from an 8th grader here.

Step-by-step explanation:

The smallest four-digit number that is divisible by each of the four smallest prime numbers is 1050.

What is the divisibility rule?

The divisibility rule states that " Divisible By, implies that when two numbers are divided, the result would be a whole number.

The four smallest prime numbers are 2, 3, 5, and 7.

To find the smallest four-digit number that is divisible by each of these numbers, we can start by finding the least common multiple (LCM) of these numbers. The LCM of a set of numbers is the smallest number that is divisible by all of the numbers in the set.

To find the LCM of 2, 3, 5, and 7, we can start by listing the prime factorization of each number:

2 = 2 x 1

3 = 3 x 1

5 = 5 x 1

7 = 7 x 1

Then, we can find the LCM by taking the highest power of each prime that appears in any of the numbers:

LCM(2, 3, 5, 7) = 2¹ x 3¹ x 5¹ x 7¹  = 210

Since we want the "smallest 4-digit number", then it is:

210 x 5 =1050

Therefore, each of the four lowest prime numbers may be divisible by the smallest four-digit number, which is 1050.

Learn more about the divisibility rule here:

brainly.com/question/10703980

#SPJ2

How much simple interest would Kaitlin earn on $300 at 6% for 3 months?

A. 27

B. 9

C. 54

D. 18

Answers

Answer:

C) $54.00

Step-by-step explanation:

300*6%*3

300*0.06*3

which is $54.

Hope this helps plz hit the crown :D

The correct answer is C

Prove that x+1 is a factor of x^n+1 where n is an odd positive integer.​

Answers

Answer:

because x^n+1 =

the number which is n and n is an odd number and my odd number is 3 so

x^3+1= 4

= x^4

Find 83 1/3 % of 384

Answers

Answer:

319.872

Step-by-step explanation:

319.872 / 384 = 83 1/3 / 100

Final Answer: [tex]320[/tex]

Steps/Reasons/Explanation:

Question: Find [tex]83\frac{1}{3}[/tex]% of [tex]384[/tex].

Step 1: Convert mixed fraction into improper fraction.

[tex]\frac{250}{3}[/tex]

Step 2: Multiply [tex]\frac{250}{3 * 100}[/tex] with [tex]384[/tex].

[tex]\frac{96000}{300}[/tex]

Step 3: Simplify

[tex]320[/tex]

~I hope I helped you :)~

The rate of change in sales S is inversely proportional to time t(t > 1) measured in weeks. Find S as a function of t if sates after 2 and 4 weeks are 200 units and 350 units respectively.
A. S(t) = 50 [3 ln t/ln2 +1]
B. S(t) = 550 [3 ln t/ln3 +150]
C. S(t) = 50 [3 ln t/ln2 +11]
D. S(t) = 50 [11 ln t/ln2 +1]
E. S(t) = 550 [ln t/ln3 +1]

Answers

Answer:

A. S(t) = 50 [3 ln t/ln2 +1]

Step-by-step explanation:

We are told that the rate of change in sales S is inversely proportional to time.

Thus;

dS/dt = k/t

Where k is the constant of proportionality.

So,

dS = (k/t)dt

Integrating both sides gives us;

S = (kIn t) + C

We are given that after 2 and 4 weeks are 200 units and 350 units respectively.

Thus;

S(2);

(k In 2) + C = 200 - - - (eq 1)

(k In 4) + C = 350 - - - -(eq 2)

To find k, let's subtract eq 1 from eq 2 to get;

(k In 4) - (k In 2) = 350 - 200

(k In 4) - (k In 2) = 150

k(In 4 - In 2) = 150

0.6931k = 150

k = 150/0.6931

k = 216.42

Plugging this for k in eq 1 gives;

(216.42 In 2) + C = 200

C = 200 - 150

C = 50

Thus;

S(t) = (216.42In t) + 50

Now 216.42 can also be expressed as;

150/In 2

Thus;

S(t) = ((150/In 2)In t) + 50

Factorizing out gives;

S(t) = 50 [(3 ln t/ln2) + 1]

Option A is the correct answer

0 = 4 + n/5 two step equations​

Answers

Answer: n= -20?

Step-by-step:

Simplify both sides of the equation

1/5n+4=0

Then subtract 4 from both sides

1/5n + 4 - 4 = 0 - 4

1/5n= -4

Then multiply both sides by 5

5*(1/5n)=5*(-4)

Answer:

0=n

Step-by-step explanation:

1. 0=4+n/5

add 4 and n

2. 0=4n/5

×5. ×5

3. 0=4n

-- --

4 4

4. 0=n

Look at the picture for a more detailed steps

Three less than half of a number is - 1. Find the number.

Answers

Answer:

x = 4

Step-by-step explanation:

Three less than half of a number is -1

The Half Of A Number means the number can be anything, so we can use "x." However, it is half so it would become: 1/2x.

Three less than means it is minus three, therefore becomes: 1/2x-3

However, three less than half of a number is (or in other words is equal too) -1,  so the overall equation is

1/2x - 3 = -1

first, add three on both sides to get:

      1/2x = 2

multiply two on both sides to get:

     x = 4

Nadine's curtain company is making curtains for a local hotel. She wants each curtain to be 48 inches long. At the fabric store, fabric is sold by the foot. If Nadine's curtain company wants to make 52 curtains, how many feet of fabric will she need? 1 inch = 1 12 foot

Answers

Bsnsnssssa n jnsjssa sss

Estabon poured himself a hot beverage that had a temperature of 201 F then set it on the kitchen table to cool. The temperature of the kitchen was a constant 68F. If the drink cooled to 181F IN 4 minutes, how long will it take for the drink to cool to 104F?

Answers

Answer:

Fifteen minutes and twenty-four seconds.

Step-by-step explanation:

In four minutes, Estabon's drink cooled down 20 degrees (201 - 181 = 20). This means that the drink cooled down five degrees a minute. The drink must cool down 77 more degrees, (181 - 104 = 77). 77 divided by 5 is 15.4. 15.4 translated to seconds is 15 minutes and 24 seconds.

In the rectangle below, AChas a length of 32 units. What is the length of DE?
O A. 32 units
OB. 64 units
OC. 24 units
O D. 16 units

Answers

D is the answer for the question

thx for helping me get smart and learing my math ava :D

Answers

Answer:

NICEE

Step-by-step explanation:

What's the midpoint between 3 and -5

Answers

Answer:

Step-by-step explanation:

just imagine you are on a number line and the numbers are

-5....-4.....-3.....-2....-1....0....1....2.....3

as you see the midpoint is -1

HELP IM IN CLASS DOING IT RIGHT NOW The absolute value of any number is always positive. True False

Answers

Answer:

True

Step-by-step explanation:

Answer:

[tex] \huge\purple{TRUE}[/tex]

Step-by-step explanation:

The absolute value of any number is always positive.

Which shows the use of the associative and commutative properties to make simplifying 3.2 + 20 – 3+ 4.8 + 19 easier?​

Answers

Answer:

B

Step-by-step explanation:

(3.2+4.8)+[20+19+(-4)]

8. +. 47. -4

=43

Santiago starts a savings account with $20. Each month he deposits $15 more into the account. Santiago wants to save a least $80. Write an inequality that represents this situation.

Answers

Answer:

$20 + $15m ≥ $80

Step-by-step explanation:

He starts off with $20.

He adds $15 each month, so $15m.

He wants to save at least $80, which means greater than or equal to $80. So, you use this symbol: ≥

Put it all together.

$20 + $15m ≥ $80

Hope that helps.

Enter the number that belongs in the green box cd=

Answers

57 because it is right n mark ne brain list please

Answer:

9

Step-by-step explanation:

I think 9 since there’s a right angle, so there’s an assumed right angle on the other side of the line. 9 is the hypotenuse when AB is 3 so I think CD would also be 9 since BC is 3 as well.

21. Transportation A youth group with 26 members is going skiing. Each of the five
chaperones will drive a van or sedan. The vans can seat seven people, and the
sedans can seat five people. Assuming there are no empty seats, how many of each
type of vehicle could transport all 31 people to the ski area in one trip?

Answers

Answers:

2 sedans and 3 vans

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

Work Shown:

s = number of sedans

v = number of vans

1 sedan = 5 seats

s sedans = 5s seats

1 van = 7 seats

v vans = 7v seats

5s+7v = all seats

5s+7v = 31

Let's go through all the values of s to see which values of v work.

If s = 0, then the equation turns into 7v = 31, but the solution for v isn't an integer.If s = 1, then the equation turns into 5+7v = 31 and that solves to v = 26/7 = 3.71 which also isn't an integerIf s = 2, then the equation becomes 10+7v = 31 and that solves to v = 3. So we found the answer. This means we need 2 sedans and 3 vans.

As a check:

2 sedans = 5*2 = 10 seats

3 vans = 7*3 = 21 seats

10+21 = 31 seats total

This confirms the answer.

The number of vans used is three and the number of sedans is two

Let :

v represent the number of vans

s represent the number of sedans

The following equations can be gotten

7v + 5s = 31 equation 1

v + s = 5 equation 2

The elimination method would be used to solve for v and s

Multiply equation 2 by 7

7v + 7s = 35 equation 3

Subtract equation 1 from 3

2s = 4

s = 4/2

s = 2

Substitute for s in equation 2

v + 2 = 5

v = 5 - 2

v = 3

To learn more about simultaneous equations, please check: brainly.com/question/23589883?referrer=searchResults

-4y-4+(-3) please help me! thank you

Answers

Answer: 1.75 = y

Explanation: In the picture linked

Hope this helps

Darnelle has a $10,000, three-year loan with an APR of 5%. She uses the table on page 159 to compute information on the loan,
a. What is her monthly payment?
b. What is the total of all her monthly payments?
c. What is the total finance charge?
HELP

Answers

Her monthly payment would be $180.56, the total of all her monthly payments would be $13,000 and the total finance charge is $3000.

What is the expression of simple interest?

The expression for the final amount for simple interest is

A = p(1+rt)

Given data

Principal = $10,000

Rate= 5 %= 0.05

Time = 6years (Assume)

A = p(1+rt)

A = 10,000(1+0.05×6)

A = 10,000(1+0.30)

A = 10,000(1.30)

A = 13,000

So the final amount for simple interest is $13,000

To determine her monthly payment

Given that it is spread over 6 years

There are 12×6 months= 72months

So monthly pay = 10000/72 = $180.56

The total of all her monthly payments would be $13,000 which is equal to the final amount.

The finance charge is equal to the interest.

⇒ $13,000 - $10,000 = $3000

So the finance charge would be $3000.

Therefore, her monthly payment would be $180.56, the total of all her monthly payments would be $13,000 and the total finance charge is $3000.

Learn more about the simple interest here:

brainly.com/question/22621039

#SPJ5

Find the cost of tiling a rectangular plot of land 300 m long and 150 m wide at the rate of $6 per square m.

Answers

Answer:

$270,000

Step-by-step explanation:

First, find the area of the plot using the formula A = lw

A = lw

A = (300)(150)

A = 45,000

Then, multiply this by 6 to find the total cost:

45,000(6)

= 270,000

So, the cost to tile the plot is $270,000

Answer:

2700

Step-by-step explanation:

Length= 300m

width= 150 m

Area = Lx W = 300 x 150= 4500 sq m

rate per 100 sq meter= 6

so total cost = 4500/ 100 x 6

= 2700

hope it helps!

At a sale, dresses were sold for $22 each. This price was 55% of a dress's original price. How much did a dress originally cost? Answer: Submit Answer attempt 1 out o Privacy Policy Terms of Service acer​

Answers

Answer:

$9.90

Step-by-step explanation:

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Answers

Answer:

y = 64

Step-by-step explanation:

The angles are supplementary, that is sum to 180° , thus

2(x + 6) + y = 180 ← substitute x = 52

2(52 + 6) + y = 180

2(58) + y = 180

116 + y = 180 ( subtract 116 from both sides )

y = 64

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