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.
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)
An average scanned image occupies 0.5 megabytes of memory with a standard deviation of 0.2 megabytes. If you plan to publish 80 images on your web site, what is the probability that their total size is between 49 megabytes and 53 megabytes?
Answer:
Approximately [tex]0.012[/tex] (that's approximately [tex]1.2\%[/tex].)
Step-by-step explanation:
The question did not specify the exact distribution of the size of those images. However, the sample size [tex]n = 80[/tex] is a rather large number. Assume that:
the sizes of these [tex]80[/tex] images follow the same distribution, with mean [tex]\mu = 0.5[/tex] megabytes and standard deviation [tex]\sigma = 0.2[/tex] megabytes.the size of each image is independent of one another.If both assumptions are met, the central limit theorem would apply. This theorem would suggest that the sum of the sizes of these [tex]80[/tex] image (a random variable) will approximately follow a normal distribution. The mean of that sum would be approximately [tex]n\cdot \mu= 80 \times 0.5[/tex]. The standard deviation of that sum would be approximately [tex]\sigma\, \sqrt{n} = 0.2\times \sqrt{80}[/tex].
Let [tex]\displaystyle \Sigma X[/tex] denote the sum of these eighty sizes.
Under these assumption, [tex]\displaystyle \Sigma X \stackrel{\text{app.}}{\sim} \mathrm{N}\left(n\, \mu,\, \sigma\,\sqrt{n}\right)[/tex].
That is: [tex]\displaystyle \Sigma X \stackrel{\text{app.}}{\sim} \mathrm{N}\left({80\times 0.5},\, \left(0.2\times \sqrt{80}\right)^2}\right)[/tex].
The question is asking for the probability [tex]P(49 \le \Sigma X \le 53)[/tex]. Therefore, calculate the [tex]z[/tex]-score that corresponding to [tex]\Sigma X = 49[/tex] and [tex]\Sigma X = 53[/tex]:
For [tex]\Sigma X = 49[/tex], the [tex]z[/tex]-score would be [tex]\displaystyle \frac{\sum X - n\, \mu}{\sigma \sqrt{n}} = \frac{49 - 80 \times 0.5}{0.2\times \sqrt{80}} = 2.25[/tex].For [tex]\Sigma X = 53[/tex], the [tex]z[/tex]-score would be [tex]\displaystyle \frac{\sum X - n\, \mu}{\sigma \sqrt{n}} = \frac{53 - 80 \times 0.5}{0.2\times \sqrt{80}} = 3.25[/tex].Make use of a [tex]z[/tex]-table to find these two probabilities:
[tex]P(X \le 49) = P(Z < 2.25) \approx 0.98778[/tex].[tex]P(X \le 53) = P(Z < 3.25) \approx 0.99942[/tex].Calculate the probability that this question is asking for:
[tex]\begin{aligned}& P(49 \le \Sigma X \le 53) \\ &= P(\Sigma X < 53) - P(\Sigma X < 49) \\ & \approx 0.99942 - 0.98778 \approx 0.012 = 1.2\%\end{aligned}[/tex].
there are 7209 students at a amusement park. to the nearest thousands, how many students are in the park
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.
What power of 10 makes number 3 equal 3,000
Answer:
3 power of 10 makes number 3 equal 3000
Step-by-step explanation:
10*10*10=1000
3*1000=3000
Answer:
3 x 10^3
Step-by-step explanation:
3 x 10^3
3 x 1000
3000
hope this helps, pls mark brainliest :D
The cost of 3 scarves is $26.25. What is the unit price? (cost per scarf)
$8.75 because 26.25 divided by 3 equals $8.75.
hope this helps
Which expression is equivalent to -3(4x-0.50)?
PLEASEEEEEEEEEEEEE HELPPP
Final Answer: [tex]-12x + 1.5[/tex]
Steps/Reasons/Explanation:
Question: Which expression is equivalent to [tex]-3(4x - 0.50)?[/tex]
Step 1: Expand by distributing terms.
[tex]-3[/tex] × [tex]4x - 3[/tex] × [tex]-0.50[/tex]
Step 2: Simplify [tex]-3[/tex] × [tex]4x[/tex] to [tex]-12x[/tex].
[tex]-12x - 3[/tex] × [tex]-0.50[/tex]
Step 3: Simplify [tex]3[/tex] × [tex]-0.50[/tex] to [tex]-1.5[/tex].
[tex]-12x - (-1.5)[/tex]
Step 4: Remove parentheses and add.
[tex]-12x + 1.5[/tex]
~I hope I helped you :)~
It Snowed 1/2 inch on Saturday and 1 3/5 inches on Sunday. How much did it snow altogether, total?
Answer:
Fraction form: it snowed 2 1/10 inches in total, decimal form: in other words it snowed 2.1 inches.
Step-by-step explanation:
HELP PLEASE I GIVE BRAINLIEST
Answer:
30
Step-by-step explanation:
Perimeter of rectangle = 5y - 1 + 4y + 2 + 5y - 1 + 4y + 2
= 18y + 2
18y + 2 = 128
18y = 128 - 2
= 126
y = 126 ÷ 18
y = 7
Length of AD = 4y + 2
= 4(7) + 2
= 28 + 2
= 30
Hurry plz!!
For parts (b) and (c), type each answer in the box below.
b. Explain why the opposite of a positive number will always be a negative
number
C. Explain why zero is its own opposite number.
Please help me fast!!!. Joe and his family are touring Chicago. They want to visit the Willis Tower, hang out at Navy Pier, and shop on Michigan Avenue before their dinner reservations at 5:10 P.M. They plan to spend 1 hour and 10 minutes at the Willis Tower, 3 hours and 10 minutes at Navy Pier, and 1 hour and 15 minutes shopping. What is the latest time Joe's family can start their tour of Chicago and still make it to dinner on time?
Include A.M. or P.M. in your answer.
Answer:
11:10 am.
Step-by-step explanation:
The first thing I'm going to do is to add all the given time together
Total time = time spent at Willis tower + time spent at Navy Pier + time spent shopping
Total time = 1 HR and 10 minutes + 3 HR and 10 minutes + 1 hour and 15 minutes
Total time = (1 + 3 + 1) hr + (10 + 10 + 15) minutes
Total time = 5 hours + 35 minutes
The question doesn't make mention of how long they spent making the journey so, I'm assuming they spent 35 minutes driving around from Willis to the Pier and finally while shopping
Time = total time + time spent driving
Time = 5 hours 35 minutes + 35 minutes
Time = 6 hours and 10 minutes
Now, this time we've calculated, is what we're going to subtract from the dinner time to get our final answer
Needed time = dinner time - time
Needed time = 5:10 pm - 6:10
Needed time = 17:10 - 6:10
Needed time = 11:10
This means that they ought to start their tour by 11:10 am, so that they can meet their dinner
One year ago, Lindsey deposited $250 into a savings
account. Her balance is now $253. Two years ago, Jenn
deposited $250 into a savings account. Her balance is
now $257.50. Which account has the greater simple
interest rate? Explain.
Answer:
Jenn's account
Step-by-step explanation:
Given that:
LINDSAY'S ACCOUNT :
Principal = amount deposited = $250
Final Amount after 1 year = $253
Period (t) = 1 year
JENN'S ACCOUNT :
Principal = amount deposited = $250
Final Amount after 2 years = $257.50
Period (t) = 2 year
Using the relation :
A = P(1 + rt)
A = final amount ; r = interest rate ; t = time
Lindsay :
253 = 250(1 + r(1))
253 = 250 + 250r
253 - 250 = 250r
3 = 250r
r = 3/250
r = 0.012 ; (0.012 * 100) = 1.2%
Jenn:
257.50 = 250(1 + r(2))
257.50 = 250 + 500r
257.50 - 250 = 500r
7.50 = 500r
r = 7.50/500
r = 0.015 ; (0.015 * 100) = 1.5%
Hence, JENN'S deposit has the greater interest rate. (1.5 > 1.2)%
Answer:Sample response:Lindsay’s interest is $3 for one year. Using the formula for interest, I = prt, Lindsey’s money is earning at a rate of 1.2%. Jenn has earned $3.75 for one year. Her money is earning at a rate of 1.5%, which is a higher interest rate.
Step-by-step explanation: please make me brainliest
In the lab, Karen has two solutions that contain alcohol and is mixing them with each other. She uses 3 times as much Solution A as Solution B. Solution A is 10% alcohol and Solution B is 15% alcohol. How many milliliters of Solution B does she use, if the resulting mixture has 180 milliliters of pure alcohol?
Answer:
She uses 162 millitiers if Solution B.
Step-by-step explanation:
180 - 10% = 162
Solution A = 18 milliliters
Soultion B = 162 millitiers
Find the value of the variable that results in congruent triangles
1.
Answer:
x = 26
Step-by-step explanation:
m<B = m<E = (x + 17)°
180 - (25 + 112) = (x + 17) (sum of ∆)
180 - 137 = x + 17
43 = x + 17
Subtract both sides by 17
43 - 17 = x
x = 26
What’s three more than seventeen?
Write a story problem using the measurement interpretation of division for the following ¾ ÷ ⅛
Answer:
there was 3/4 of a pizza left and gets divided with 8 people
Step-by-step explanation:
The measurement interpretation of the division of the expression ¾ ÷ ⅛ will be 6.
What is Algebra?Algebra is the study of algebraic expressions, while logic is the manipulation of those concepts.
The acronym PEMDAS stands for Parenthesis, Exponent, Multiplication, Division, Addition, and Subtraction. This rule is used to answer the problem correctly and precisely.
The numbers are given below.
¾ and ⅛
Then the division between the numbers 6 and 1/3 will be given by putting a division sign between them. Then we have
⇒ ¾ ÷ ⅛
⇒ (¾) / (⅛)
⇒ (¾) × (⁸/₁)
⇒ 6
The measurement interpretation of the division of the expression ¾ ÷ ⅛ will be 6.
More about the Algebra link is given below.
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Michelin Tire Company wishes to set a minimum mileage guarantee on its new MX100 tire. Tests reveal the mean mileage is 67,900 with a standard deviation of 2,050 miles and that the distribution of miles follows the normal probability distribution. Michelin wants to set the minimum guaranteed mileage so that no more than 4 percent of the tires will have to be replaced. What minimum guaranteed mileage should Michelin announce
Answer:
The minimum guaranteed mileage is [tex]x = 71489.55[/tex]
Step-by-step explanation:
From the question we are told that
The mean is [tex]\mu = 67900[/tex]
The standard deviation is [tex]\sigma = 2050[/tex]
Generally for the probability to be 4% the minimum guaranteed mileage is evaluated as
[tex]P( X \ge x ) =1- P( \frac{X - \mu }{\sigma } < \frac{ x - 67900 }{ 2050} ) = 0.04[/tex]
[tex]\frac{X -\mu}{\sigma } = Z (The \ standardized \ value\ of \ X )[/tex]
[tex]P( X \ge x ) =1- P( Z<z) = 0.04[/tex]
=> [tex]P( X \ge x ) = P( Z<z) = 0.96[/tex]
=> [tex]z = \frac{ x - 67900 }{ 2050}[/tex]
From the z table, the critical value corresponding to 0.96 to the left of the curve is
[tex]z = 1.751[/tex]
So
[tex]1.751 = \frac{ x - 67900 }{ 2050}[/tex]
=> [tex]x = 71489.55[/tex]
Deborah spent $70 on food and clothes she spent $26 more on clothes then on food Brighton solve a system of equations to find how much Debra spent on each
Answer:
Step-by-step explanation:
You know the total will be $70.
She bought food, let's call that "F"
She spent $26 more on clothes than food. So her clothes purchase is "F+26".
So let's set-up the equation this way:
food + clothing = Total Spent
F + F + 26 = 70
2F + 26 = 70 (subtract 26 from both sides of the = sign)
2F = 44 (Divide both sides so you find out how much was spent on "F" or food.)
F = 22 (But the question doesn't stop there.)
Deborah spent $22 on food. (Remember, she spent $26 more on clothes, so we have to use our "clothes" equation? ) Deborah spent $48 on clothes. She spent a total of $70 on her purchases.
0.50(61 + 3s)
Use the Distributive Property to expand the expression.
Answer:
30.5 + 1.5s
Step-by-step explanation:
An envelope is 60 centimeters wide. About how many inches wide is the envelope? (1 inch ≈ 2.5 centimeters)
Answer:
60/2.5 = 24 cm
Step-by-step explanation:
if you are satisfied with the results then plz make me genius
Answer:
The answer is 24 inches.
Step-by-step explanation:
Given:
1 inch = 2.5 cm
or, 1 cm = 1/2.5 inch............... eqn (i)
Now,
Wideness of envelope = 60 cm
= 60 (1/2.5) inches [From eqn (i)]
= 60/2.5 inches
= 24 inches Ans
24 = 3y Solve for y and show work
Answer:
y=8
Step-by-step explanation:
because 3×8 is 24
and 8 would be the missing number
Solve for g .
g + (-5) = 27
g =
Final Answer: [tex]g = 32[/tex]
Steps/Reasons/Explanation:
Question: Solve for [tex]g[/tex]. [tex]g + (-5) = 27[/tex]. [tex]g[/tex] = ?
Step 1: Remove parentheses.
[tex]g + -5 = 27[/tex]
Step 2: Simplify [tex]g + -5[/tex] to [tex]g - 5[/tex].
[tex]g - 5 = 27[/tex]
Step 3: Add [tex]5[/tex] to both sides.
[tex]g = 27 + 5[/tex]
Step 4: Simplify [tex]27 + 5[/tex] to [tex]32[/tex].
[tex]g = 32[/tex]
~I hope I helped you :)~
6464 is 444 times the difference between Sarah's age, aaa, and 444444. Assume Sarah is older than 44
Answer:
60 years
Step-by-step explanation:
Given that :
Sarah's age = a
Assume Sarah is older than 44 ; then a > 44
64 = 4 times difference between a and 44
Expressing the problem mathematically ;
64 = 4 * (a - 44)
64 = 4a - 176
64 + 176 = 4a
240 = 4a
a = 240 / 4
a = 60
Hence, Sarah is aged 60
How many points will I get if I get 60 points every 5 mins and it goes on for 4 hours?
Answer:
well u multiply 60 and 12 which is 720 then multiply that by 4 that equals 2,880 more points
HELPPP I NEED AN ANSWER ASAP
Answer:
2, 4, and 6 (b, d, f)
Step-by-step explanation:
dont really know how to explain
describe the relationship between the similarity ratio of two triangles and the ratio of their areas. help plz
Answer:
When two triangles are similar, the reduced ratio of any two corresponding sides is called the scale factor of the similar triangles.
Step-by-step explanation:
Theorem 60: If two similar triangles have a scale factor of a : b, then the ratio of their perimeters is a : b.
Help me pleaseeeeeeeeeeeeeeeeeeeeeeeeeeeeeee
Answer:
A, 2 5/8 cups
Step-by-step explanation:
Since six dozen brownies is three times as much as two dozen, we can multiply 7/8 cups by 3. 3 x 7/8 = 21/8 If we simplify this fraction, it is 2 5/8. Therefore the answer is A, 2 5/8 cups.
66% of 62 is...? **SHOW YOUR WORK** PLEASE HELP!! :'(
Step-by-step explanation:
divide 62 by 100 and then multiply that number by 66. I don't have a calculator on me rn sorry
Answer:
Fraction:
[tex]\frac{1023}{25}[/tex]
Decimal:
40.92
Mixed Number:
[tex]40\frac{23}{25}[/tex]
Step-by-step explanation:
66% is the same this as [tex]\frac{66}{100}[/tex]. You can simplify [tex]\frac{66}{100}[/tex] to [tex]\frac{33}{50}[/tex]. Then, find [tex]\frac{33}{50}[/tex] of 62, which is the same thing as [tex]\frac{33}{50}[/tex] x 62. You’ll get either of the three options, a fraction, decimal, or a mixed number, but all three are the same thing (you get to choose which one).
Hope this helps! :)
1 1/6 as an improper fraction
Answer:
The mixed number 1 1/6 converted into an improper fraction is 7/6.
Step-by-step explanation:
The improper fraction representation after converting of 1 1/6 is 7/6 where numerator is 7 and denominator is 6
To convert a mixed number to an improper fraction, we follow these steps:
Multiply the whole number by the denominator of the fraction.
In this case, multiply 1 (the whole number) by 6 (the denominator), which gives 6.
Add the numerator to the result obtained in step 1.
The numerator in this case is 1. Adding 1 to 6 gives 7.
Place the result from step 2 as the numerator of the fraction, and keep the denominator the same.
The denominator remains 6.
Therefore, the improper fraction representation of 1 1/6 is 7/6.
Learn more about converting fractions here:
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Triangle PQR is rotated 180 clockwise about point m and the image of point p is p and the image of point r is r what are the coordinates of the image of point Q
Answer:
Rotating 180 clockwise would mean that Q is Q if r is r, the coordinates of it pointing to Q would be in your picture , can I see a picture of the problem?
Step-by-step explanation:
Find the are of the semi circle.Either enter an exact answer in terms of pie or use 3.14 and enter your answer as a decimal.The raduis is 4