Answer:
False
Step-by-step explanation:
It costs 114 Billion annually
Answer:
true duhhh
Step-by-step explanation:
As part of the Pew Internet and American Life Project, researchers conducted two surveys in late 2009. The first survey asked a random sample of 800 U.S. teens about their use of social media and the internet. A second survey posed similar questions to a random sample of 2253 U.S. adults. In these two studies, 73% of teens and 47% of adults said that they use social networking sites. Use these results to construct and interpret a 95% confidence interval for the difference between the proportion of all U.S. teens and adults who use social networking sites.
Answer:
The 95% confidence interval for the difference between the proportion of all U.S. teens and adults who use social networking sites is (0.223, 0.297). This means that we are 95% sure that the true difference of the proportion is in this interval, between 0.223 and 0.297.
Step-by-step explanation:
Before building the confidence interval we need to understand the central limit theorem and the subtraction of normal variables.
Central Limit Theorem
The Central Limit Theorem estabilishes that, for a normally distributed random variable X, with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean [tex]\mu[/tex] and standard deviation [tex]s = \frac{\sigma}{\sqrt{n}}[/tex].
For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.
For a proportion p in a sample of size n, the sampling distribution of the sample proportion will be approximately normal with mean [tex]\mu = p[/tex] and standard deviation [tex]s = \sqrt{\frac{p(1-p)}{n}}[/tex]
Subtraction between normal variables:
When two normal variables are subtracted, the mean is the difference of the means, while the standard deviation is the square root of the sum of the variances.
Sample of 800 teens. 73% said that they use social networking sites.
This means that:
[tex]p_T = 0.73, s_T = \sqrt{\frac{0.73*0.27}{800}} = 0.0157[/tex]
Sample of 2253 adults. 47% said that they use social networking sites.
This means that:
[tex]p_A = 0.47,s_A = \sqrt{\frac{0.47*0.53}{2253}} = 0.0105[/tex]
Distribution of the difference:
[tex]p = p_T - p_A = 0.73 - 0.47 = 0.26[/tex]
[tex]s = \sqrt{s_T^2+s_A^2} = \sqrt{0.0157^2+0.0105^2} = 0.019[/tex]
Confidence interval:
Is given by:
[tex]p \pm zs[/tex]
In which
z is the zscore that has a pvalue of [tex]1 - \frac{\alpha}{2}[/tex].
95% confidence level
So [tex]\alpha = 0.05[/tex], z is the value of Z that has a pvalue of [tex]1 - \frac{0.05}{2} = 0.975[/tex], so [tex]Z = 1.96[/tex].
Lower bound:
[tex]p - 1.96s = 0.26 - 1.96*0.019 = 0.223[/tex]
Upper bound:
[tex]p + 1.96s = 0.26 + 1.96*0.019 = 0.297[/tex]
The 95% confidence interval for the difference between the proportion of all U.S. teens and adults who use social networking sites is (0.223, 0.297). This means that we are 95% sure that the true difference of the proportion is in this interval, between 0.223 and 0.297.
HELPPPPPPPPPP FAST PLSSSSSSSSSSSSSSSSSSSSS
What value of N balances the scale
What is the least common multiple of 4, 6, and 12?
Answer:
12
Step-by-step explanation:
Answer:
12
Step-by-step explanation:
12,24,36,48,60,72...
12 is the smallest common multiple so LCM of 4,6 and 12 is 12
What is 5C3?
A. 35
B. 10
C. 14
D. 28
Answer: B. 10
-5C3 or 5 choose 3 refers to how many combinations are possible from 5 items, taken 3 at a time. To calculate combinations, we will use the formula nCr = n! / r! ... * (n - r)!, where n represents the total number of items, and r represents the number of items being chosen at a time.
-10 is the total number of all possible combinations for choosing 3 elements at a time from 5 distinct elements without considering the order of elements in statistics & probability surveys or experiments. The number of combinations for sample space 5 CHOOSE 3 can also be written as 5C3 in the format of nCr or nCk.
Step-by-step explanation: Hope this help :D
Which statement is true about the equations -3x + 4y = 12 and %x-Ay=17
O The system of the equations has exactly one solution at (-8, 3).
The system of the equations has exactly one solution at (-4, 3).
The system of the equations has no solution, the two lines are parallel.
O The system of the equations has an infinite number of solutions represented by either equation.
Answer:
No solution, the lines are parallel.
Step-by-step explanation:
Any line can be represented by the equation
y = mx + b
where m is the slope and b is the y intercept.
-3x + 4y = 12
4y = 3x + 12
y = 3/4 x + 3
AND
1/4 x - 1/3 y = 1
- 1/3 y = - 1/4 x + 1
-4y = -3x + 12
4y = 3x - 12
y = 3/4 x - 3
If you get both equations in this form it is evident that the slopes m are the same (parallel) but the y intercept's b are different (not the same line). Therefore no solution.
What is the volume of this figure? Pls help this is due Thursday 11:45
Answer:
The answer for this question is 49 cubic inches
If Bill hiked 6.5 miles at a rate of 10.4 mph, how long did it take him to complete his hike?
Answer:
32 minutes or .5333 of an hour
Step-by-step explanation:
IS A PICTURE!!!! thank you for your time
Answer:
I am not sure, but I think you would check for the side with the longest length(hypothenuse) and check if the formula of a^2+b^2=c^2(side with the longest length) satisfies it.
HELP ASAP!!
Combine like terms:
-7x + 8 - 4x - 9
answers:
1. -11x - 1
2. -3x - 1
3. -11x + 17
4. -12
Answer:
The answer for -7x + 8 - 4x - 9 is 1. -11x-1
How many tenths are in 8.32?
Answer:
3 tenths
Step-by-step explanation:
Aside from the vertex, the horizontal cross-sectional shapes of this pyramid
are all similar rectangles.
O A. True
B. False
The length of a vegetable garden is 5 times its width. If its width is 3/4 meter, what is the area?
When building a house, the number of days required to build varies inversely with
with the number of workers. One house was built in 11 days by 49 workers. How
many days would it take to build a similar house with 7 workers?
Answer: 77 days
Step-by-step explanation:
Solve -7 2/3+(-5 1/2)+8 3/4=
Answer:
-53/12
Step-by-step explanation:
Answer:
Exact Form: -53/12
decimal form: -4.416
mixed number -4 5/12
Step-by-step explanation:
convert mixed numbers into improper fractions: -2 3/3 +(5 1/2)+ 8 3/4
convert mixed numbers into improper fractions: =11/2 =[tex]-\frac{23}{3}+\left(-\frac{11}{2}\right)+\frac{35}{4}[/tex] =
[tex]-\frac{23}{3}+\left-\frac{11}{2}\right+\frac{35}{4}[/tex][tex]=-\frac{92}{12}-\frac{66}{12}+\frac{105}{12}[/tex]
[tex]\frac{-92-66+105}{12}[/tex]
add/subtract the numbers: -92-66+105=-53
-53/12
apply the fraction rule: [tex]\frac{-a}{b} = -\frac{a}{b\\}[/tex]
[tex]=-\frac{53}{12}\\[/tex]
PLEASE HELP THIS IS DUE SOON!
Sales Hester sells televisions. She earns a fixed amount for each television and an additional $20if the buyer gets an extended warranty. If Hester sells 19 televisions with extended warranties, she
earns $1,710. How much is the fixed amount Hester earns for each television?
The fixed amount Hester earns for each television she sells is $]
Answer:
380
Step-by-step explanation:
multiply 20 x 19
Which of the following situations can be represented by C = 10 + 0.44n?
Answer:
10.44
Step-by-step explanation:
Given the following data, what is the probability that a car will have a V8 or a manual transmission?
A- 70.06%
B-110.71%
C-76.07%
D-60.71%
pleaseee helpppp!!
Answer:
x = 148
Step-by-step explanation:
vertical angles are congruent
the angle with a measure of 148° and the angle labeled "x" are vertical angles.
Hence, x = 148
Answer:
x=148 because the opposite angles are equal
also, the rest of the smaller angles are both 32 degrees if you need them
you can check because 148+148+32+32=360
hope it helps:)
what is the answer for this one?
2x + 3 = 9. x
Answer:
3/7
Step-by-step explanation:
You want to seperate the numbers from the variable.
What is the volume of this composite solid?
Step-by-step explanation:
5×9×12=540
6×9×12÷2=324
324+540=864
Answer:
C. 1188 cubic meters
Step-by-step explanation:
"To find the volume, we must multiply the length x width x height"
The shape is too big so we must break it into another shape
Let's solve the bottom shape that looks like a rectangle!
Length: 12 m
Width: 9 m
Height: 5 m
Volume = 540 m
Now the top shape!
Length: 12 m
Width: 9 m
Height: 6 m
Volume = 648 m
Now we need to add both of the volume shapes!
648 + 540 = 1188 cubic meters
Jamie will plot (9, 5) on a coordinate plane. She knows the last step is to put a point where two lines intersect. Which two steps should she use first
Answer:
i got g
Step-by-step explanation:
Answer:
Step-by-step explanation:
G and h
what is the area of this figure?
Answer:
4 ssquare units
Step-by-step explanation:
What equation models the volume for a rectangular prism that is 4 cm long, 4cm wide, and 0.1 m tall A. V = 42 x 10 B. V = 10 x (4 + 4) C. V = 400 x 4 D. V = (4 x 4) + 10
Answer:
It's 160
I think you have a typo in d. If you do, the answer is d) V=(4 x 4) x 10
meaning a x 10 versus a + 10 as typed.
Step-by-step explanation:
.1m=10cm
volume = 4 x 4 x 10 = 160
Zoey had 15 rocks.
she put them in 3
boxes. how many
were in each box?
Answer: 5
Step-by-step explanation:
Two trains leave stations 456 miles apart at the same time and travel toward each other. One train travels at 105 miles per hour while the other travels at 105miles per hour. How long will it take for the two trains to meet?
Answer:
let x=distance 105 mph train traveled
(456-x)=distance 85 mph train traveled
Travel time = distance/speed (equal in both directions)
x/105=(456-x)/85
85x=105*456-105x
190x=105*456
x=105*456/190=252 miles
travel time=252/105=2.4 hrs
ans:
The two trains will meet in 2.4 hrs
Step-by-step explanation:
there brainliest pls
Question:
a spinner has 8 equally sized sections, six of the selections are green.
a. What is the probability that the spinner will land on green?
1. ____ out of 8, or _/4, or ____%
b. Use words to describe the probability / It is ____ that the spinner will land on green.
Help me with number 10 pleaseeeeeeeeee
Answer:
4' - 9.64
Step-by-step explanation:
Total rise = 2' - 7"
Total run = 3' - 9"
Converting to inches :
1' = 12" ; 1 feet = 12 inches
2' = 2 * 12 = 24"
3' = 3 * 12 = 36"
Total rise = 24" + 7" = 31"
Total run = 36" + 9" = 45"
Length of stringer = hypotenus
Hypotenus = √(total rise² + total run²)
Hypotenus = √(31² + 45²)
Hypotenus = 54.644304"
= 4' - 9.64"
PLEASE HELP ME
The following data set shows the pulse rate of some goats at a farm:
75, 76, 77, 76, 77, 76, 78, 75, 78, 76, 79, 76, 78, 76, 77, 76
Which dot plot best represents the data?
dot plot with 2 dots over 75, 8 dots over 76, 3 dots over 77, 3 dots over 78, no dot over 79
dot plot with 2 dots over 75, 7 dots over 76, 3 dots over 77, 3 dots over 78, 1 dot over 79
dot plot with 1 dot over 75, 8 dots over 76, 3 dots over 77, 3 dots over 78, 1 dot over 79
dot plot with 2 dots over 75, 6 dots over 76, 3 dots over 77, 3 dots over 78, 1 dot over 79
Answer: B) dot plot with 2 dots over 75, 7 dots over 76, 3 dots over 77, 3 dots over 78, 1 dot over 79
Step-by-step explanation: took the test, hope this helps c:
A newsgroup is interested in constructing a 90% confidence interval for the proportion of all Americans who are in favor of a new Green initiative. Of the 533 randomly selected Americans surveyed, 351 were in favor of the initiative. Round answers to 4 decimal places where possible.
Answer:
The 90% confidence interval for the proportion of all Americans who are in favor of a new Green initiative is (0.6247, 0.6923).
Step-by-step explanation:
In a sample with a number n of people surveyed with a probability of a success of [tex]\pi[/tex], and a confidence level of [tex]1-\alpha[/tex], we have the following confidence interval of proportions.
[tex]\pi \pm z\sqrt{\frac{\pi(1-\pi)}{n}}[/tex]
In which
z is the z-score that has a p-value of [tex]1 - \frac{\alpha}{2}[/tex].
Of the 533 randomly selected Americans surveyed, 351 were in favor of the initiative.
This means that [tex]n = 533, \pi = \frac{351}{533} = 0.6585[/tex]
90% confidence level
So [tex]\alpha = 0.1[/tex], z is the value of Z that has a p-value of [tex]1 - \frac{0.1}{2} = 0.95[/tex], so [tex]Z = 1.645[/tex].
The lower limit of this interval is:
[tex]\pi - z\sqrt{\frac{\pi(1-\pi)}{n}} = 0.6585 - 1.645\sqrt{\frac{0.6585*0.3415}{533}} = 0.6247[/tex]
The upper limit of this interval is:
[tex]\pi + z\sqrt{\frac{\pi(1-\pi)}{n}} = 0.6585 + 1.645\sqrt{\frac{0.6585*0.3415}{533}} = 0.6923[/tex]
The 90% confidence interval for the proportion of all Americans who are in favor of a new Green initiative is (0.6247, 0.6923).