Noise levels at 5 airports were measured in decibels yielding the following data:
117,118,140,116,119
1. Construct the 90% confidence interval for the mean noise level at such locations. Assume the population is approximately normal.
2. Calculate the sample mean for the given sample data.
3. Find the critical value that should be used in constructing the confidence interval.
Answer:
1. 112.364<μ,131.636
2. mean = 122
3. critical value = +-2.1318
Step-by-step explanation:
117+118+140+116+119/5
= 610/5
= 122
the sample mean = 122
the sample standard deviation
s² = (117-122)²+(118-122)²+(140-122)²+(116-122²)+(119-122)²/5-1
= 25+16+324+36+9/4
= 410/4
= 102.5
s² = 102.5
s = √102.5
s= 10.12
SE = s/√n
= 10.12/√5
= 4.52
degree of freedom = 5-1 = 4
critical value of t = +-2.1318 using soft ware
confidence interval =
mean +- t(SE)
122-(2.1318)(4.52), 122+(2.1318)(4.52)
= [112.364, 131.636]
112.364<μ,131.636
therefore these are the answers in the ordre it was given in the question
1. 112.364<μ,131.636
2. mean = 122
3. critical value = +-2.1318
in the problem 12+58=70,12 and 58 are called factors true or false
Answer:
false
Step-by-step explanation:
Answer:
false they are called addend s
HELP PLS QUICK!MIGHT GIVE BRAINLIST IF TWO PEOPLE ANSWER!
Answer: A=bh to find the area of parallelograms.
Step-by-step explanation:
Melissa and Madeline love pepperoni pizza, but sometimes they are disappointed with the small number of pepperonis on their pizza. To investigate, they went to their favorite pizza restaurant at 10 random times during the week and ordered a large pepperoni pizza. Here are the numbers of pepperoni on each pizza.
47 36 25 37 46 36 49 32 32 34
Use the 4 step method to construct and interpret a 95% confidence interval for the true mean number of pepperonis on a large pizza at this restaurant.
Answer:
(31.919,42.881)
Step-by-step explanation:
Using the t-distribution, it is found that the 95% confidence interval for the true mean number of pepperonis on a large pizza at this restaurant is (31.92, 42.88). It means that we are 95% that the true mean number of pepperonis for all large pizzas at the restaurant is within this interval.
In this problem, we will find the standard deviation for the sample, hence the t-distribution will be used.
What is a t-distribution confidence interval?The confidence interval is given by:
[tex]\overline{x} \pm t\frac{s}{\sqrt{n}}[/tex]
In which:
[tex]\overline{x}[/tex] is the sample mean.t is the critical value.n is the sample size.s is the standard deviation for the sample.For this problem:
The sample size is n = 10.Using a calculator, we have that [tex]\overline{x} = 37.4, s = 7.66[/tex].The critical value, considering a 95% confidence interval with 10 - 1 = 9 df, is of t = 2.2622.The lower bound of the interval is:
[tex]\overline{x} - t\frac{s}{\sqrt{n}} = 37.4 - 2.2622\frac{7.66}{\sqrt{10}} = 31.92[/tex]
The upper bound of the interval is:
[tex]\overline{x} + t\frac{s}{\sqrt{n}} = 37.4 + 2.2622\frac{7.66}{\sqrt{10}} = 42.88[/tex]
The 95% confidence interval for the true mean number of pepperonis on a large pizza at this restaurant is (31.92, 42.88). It means that we are 95% that the true mean number of pepperonis for all large pizzas at the restaurant is within this interval.
More can be learned about the t-distribution at https://brainly.com/question/16162795
What classification of quadrilateral is show? Explain
Please help
For 20 points
Answer:
Step-by-step explanation:
Vertex: ( -2, -25)
Axis of symmetry: -2
Suppose that grade point averages of undergraduate students at one university have a bell-shaped distribution with a mean of 2.56 and a standard deviation of 0.43. Using the empirical rule, what percentage of the students have grade point averages that are between 2.13 and 2.99
Answer:
Approximately 68% of the students have grade point averages that are between 2.13 and 2.99.
Step-by-step explanation:
The Empirical Rule states that, for a normally distributed random variable:
Approximately 68% of the measures are within 1 standard deviation of the mean.
Approximately 95% of the measures are within 2 standard deviations of the mean.
Approximately 99.7% of the measures are within 3 standard deviations of the mean.
In this question, we have that:
Mean = 2.56
Standard deviation = 0.43
What percentage of the students have grade point averages that are between 2.13 and 2.99?
2.56 - 0.43 = 2.13
2.56 + 0.43 = 2.99
Within one standard deviation of the mean, so, by the Empirical Rule:
Approximately 68% of the students have grade point averages that are between 2.13 and 2.99.
272 sweets are divided between Ram and Rahim in the ratio of 7 : 9. How many sweets do they get?
Answer:
let the ratio of ram and hari be 7x and 9x respectively
7x +9x=272
or, 16x=272
or,x=272÷16
or,x=17
ratio of ram=7x=7 × 17=119
ratio pf rahim=9x=9×17=153
change 5 feet 10 inches to centimetres
Answer:
177.8
Step-by-step explanation:
There are 30.48 centimeters per foot so multiply 30.48 by 5. And there is 2.54 centimeters in a inch so multiply 2.54 by 10. And then add the totals together to get 177.8
Find the measure of the exterior angle.
Answer:
Option (C)
Step-by-step explanation:
By the property of an exterior angle,
Exterior angle of a triangle is equal to the sum of two opposite interior angles.
(15x + 34)° = 29° + (12x + 26)°
15x + 34 = 29 + 12x + 26
15x - 12x = 55 - 34
3x = 21
x = 7
Measure of exterior angle = (15x + 34)°
= 15(7) + 34
= 105 + 34
= 139°
Option (C) is the answer.
The diameter of a circle measures 12 cm. What is the circumference of the circle?
Answer
The circumference is 37.699
Hope this answer helped you!
⭐Please consider giving brainliest!⭐
Step-by-step explanation:
the circumference of the circle with diameter 12cm=2π(d/2)=2×π×12/2=12πcm
A total surface area is _ square inches
wszystkie 5 zadań pls
Explanation is in the file
tinyurl.com/wpazsebu
Answer:
Musisz przejść do Brainly.ph, jedyny sposób, w jaki z tobą rozmawiam, to tłumacz. Brainly.com jest dla języka angielskiego
Step-by-step explanation:
Here is a circle. Points A, B, C, and D are drawn, as
well as Segments AD and BC.
D.
What is the area of the circle, in square units?
The manager of a fast-food restaurant wants to be sure that, on average, customers are served within 4 minutes from the time the order is placed. He is particularly concerned about the staff working during the early morning shift. From a random sample of 41 orders, the mean time was 3.75 minutes with a standard deviation of 1.2 minutes.
(a) Is there convincing evidence at the a = 0.05 significance level that the true mean service time during the early morning shift is less than 4 minutes?
Answer:
There is not convincing evidence at the a = 0.05 significance level that the true mean service time during the early morning shift is less than 4 minutes
Step-by-step explanation:
The null hypothesis is:
[tex]H_{0} = 4[/tex]
The alternate hypothesis is:
[tex]H_{1} < 4[/tex]
The test statistic is:
[tex]z = \frac{X - \mu}{\frac{\sigma}{\sqrt{n}}}[/tex]
In which X is the sample mean, [tex]\mu[/tex] is the value tested at the null hypothesis, [tex]\sigma[/tex] is the standard deviation and n is the size of the sample.
From a random sample of 41 orders, the mean time was 3.75 minutes with a standard deviation of 1.2 minutes.
This means that [tex]n = 41, \mu = 3.75, \sigma = 1.2[/tex]
The test-statistic is:
[tex]z = \frac{X - \mu}{\frac{\sigma}{\sqrt{n}}}[/tex]
[tex]z = \frac{3.75 - 4}{\frac{1.2}{\sqrt{41}}}[/tex]
[tex]z = -1.33[/tex]
[tex]z = -1.33[/tex] has a pvalue of 0.0918, looking at the z-table.
0.0918 > 0.05, which means that the null hypothesis is accepted, and that there is not convincing evidence at the a = 0.05 significance level that the true mean service time during the early morning shift is less than 4 minutes
A triangle has sides 12cm, 9cm and 15cm. Is the triangle right-angled? Justify your answer
Answer:
yes
Step-by-step explanation:
Yes this triangle is right angled and can be justified using the Pythagorean theorem. The theorem states that: [tex]a^{2} +b^{2} = c^{2}[/tex]. Substitute using the given values:
(9^2)+(12^2)=15^2
81 + 144 = 255
255 = 255.
It satisfies the theorem therefore it is a right angle triangle.
please help must equal 180
Solve for x.
x = [?]
2x + 9
8x + 1
help please
thank you for your help
Answer:
3(7+x²)x-2
3x(7+x²)-2
21x+3x³-2
answer fast plz sjsjzjz
Answer:
104
Step-by-step explanation:
Just separate the whole thing into two shapes. Multiply the first shape: 12 x 7 = 84
Multiply the second shape: 5 x 4 = 20
An insurance office buys paper by the ream, 500 sheets, for use in the copier, fax, and printer. Each ream lasts an average of 4 days, with standard deviation 1 day. The distribution is normal, independent of previous reams. a. Find the probability that the next ream out- lasts the present one by more than 2 days. b. How many reams must be purchased if they are to last at least 60 days with probability at least 80%
Answer:
a) the probability that the next ream out- lasts the present one by more than 2 days is 0.0787
b) the number of reams that must be purchased is 19
Step-by-step explanation:
Given the data in the question;
Lets X₁ and X₂ be the two random variables that represents the first and second ream lasts
given that both random variables follow normal distribution with mean 4 and standard deviation 1.
a)
Find the probability that the next ream out- lasts the present one by more than 2 days.
P( X₂ - X₁ > 2 ) = P( [(X₂ - X₁ - E(X₂ - X₁)) / √(V(X₂ - X₁)] > [ (2-E(X₂ - X₁))/√(V(X₂ - X₁) ]
= 1 - P( Z ≤ [2-(μ₂ - μ₁)] / [√( V(X₂) + V(X₁) ) ] )
= 1 - P( Z ≤ [2-(4 - 4)] / [√( 1 + 1 )] )
= 1 - P = ( Z ≤ 2 / √2 )
= 1 - p( Z ≤ 1.4142 )
from excel; p( Z ≤ 1.41 ) = 0.9213
P( X₂ - X₁ > 2 ) = 1 - 0.9213
P( X₂ - X₁ > 2 ) = 0.0787
Therefore, the probability that the next ream out- lasts the present one by more than 2 days is 0.0787
b)
How many reams must be purchased if they are to last at least 60 days with probability at least 80%
total value is 4n
standard deviation is nσ
so
P(nX ≥ 60 ) = 0.80
P( nX-nμ /nσ ≥ 60-nμ/nσ) = 0.80
P( Z ≥ 60-4n/n) = 0.80
1 - P( Z ≥ 60-4n/n) = 0.80
P( Z < z ) = 0.20
now since z = 60-4n/n
from standard normal table
critical value of z corresponding to cumulative area of 0.20 is -0.841
so
z = - 0.841
60-4n/n = -0.841
60 - 4n = -0.841n
60 = -0.841n + 4n
60 = 3.159n
n = 60 / 3.159
n = 18.99 ≈ 19
Therefore, the number of reams that must be purchased is 19
PLEASE HELP, IF ITS RIGHT ILL GIVE U BRAINLIEST THINGY
Answer:
The answer is 8
Step-by-step explanation:
Rotation 180° about the origin
Answer:
Step-by-step explanation:
to rotate about origin by 180 ° also means to change ( x, y) ⇔( -x,-y)
the double arrows just mean to change into.. or "transform" ( I think that there might have even been a movie about this, called "transformers" :D JK)
T=( -2, 1)
S = ( -4, 3)
R = ( -5, -2)
use the transform ( x, y) ⇔( -x,-y)
T' = (2,-1)
S' = ( 4, -3 )
R' = (5 , 2 )
if you draw this on a piece of graph paper, you'll see it's the triangle spun 180 ° around the origin :)
How many fifths are there in 3⅗
Answer:
18/5
Step-by-step explanation:
5 1/5 = 1 thus 3 are 15 + 3 = 18/5
Answer:
The answer is 18 fifths.
Step-by-step explanation:
3 = 15/3 + 3/5 = 18/3 fifths.
In ΔVWX, x = 9.1 inches, w = 5.4 inches and ∠W=161°. Find all possible values of ∠X, to the nearest 10th of a degree
Answer:
NO POSSIBLE TRIANGLES
Step-by-step explanation:
Answer:
no possible triangles
Step-by-step explanation:
Will give brainliest if the answer is correct
Answer:
The answer to 5 is 3 and the answer to 6 is -2
Step-by-step explanation:
-8=2x-14
add 14 to each side
6=2x
divide by 2
3=x
----------------------------
11x+13=-9
subtract 13 from both sides
11x=-22
divide each side by 11
x=-2
Answer:
5.x=3
6.x=-2
Step-by-step explanation:
you're welcome
Myopia in children. Myopia, also called short-sightedness, is a common visual impairment that is reaching alarming proportions worldwide. The condition typically develops in school-age children and adolescents. It has long been thought that the condition was associated with too much reading, but recent evidence suggests instead that a lack of exposure to natural outdoor light may play a role. To investigate this new theory, researchers compared rates of myopia among randomly selected young children (6 and 7 years old) of Chinese ethnicity living in either Sydney (Australia) or Singapore. The researchers found that 4 of the 124 children in the Australian sample had myopia, compared with 183 among the 628 children from Singapore.
a. Display the findings in a two-way table. What percent of the children in the study had myopia? What is that percent among the children living in Australia and among those living in Singapore?
b. The researchers obtained information for most of the children in the study about their weekly amount of time in hours) spent reading or writing and the weekly amount of time in hours) spent on outdoor activities. Here are the summary statistics:
Time reading/writing Number of children Mean Standard deviation
Australia 109 20.8 13.9
Singapore 611 17.8 8.8
Time outdoors Number of children Mean Standard deviation
Australia 102 13.75 1.02
Singapore 586 3.05 0.12
How do the children from both countries in this study differ in how they spend their time?
c. Does the study suggest that more time spent reading or writing is associated with a greater risk of myopia among the enrolled children? Does it suggest that more time spent outdoors is associated with a greater risk of myopia? Can we draw a conclusion of causality based on this study?
d. The children enrolled in this study were all of Chinese ethnicity. What is the advantage in this study of collecting data from children with the same ethnicity compared with selecting random samples of children from each location regardless of ethnicity?
Answer:
a. A two way table is presented as follows;
[tex]\begin{array}{cccc}&Had \ Myopia&Do \ not \ have \ Myopia& Totals\\Sydney \ (Australia)&4&120&128\\Singapore&183&445&628\end{array}[/tex]
ii) The percentage of students in the study that have myopia are approximately 24.867%
iii) The percentage of children living in Australia with myopia are approximately 3.2258%
The percentage of children living in Singapore with myopia are approximately 29.14%
b. Children in Australia spend more time reading, writing and also outdoors than children in Singapore
c. The study does not suggest that more time spent reading or writing is associated with a greater risk of myopia among the enrolled children
The study does not suggests that more time spent outdoors is associated with a greater risk of myopia
d. The advantage is to reduce associated variables the generate more accurate findings or result
Step-by-step explanation:
a. A two way table is presented as follows;
[tex]\begin{array}{cccc}&Had \ Myopia&Do \ not \ have \ Myopia& Totals\\Sydney \ (Australia)&4&120&128\\Singapore&183&445&628\end{array}[/tex]
ii) The percentage of students in the study that have myopia are;
(4 + 183)/(124 + 628) × 100 ≈ 24.867%
iii) The percentage of children living in Australia with myopia is given as follows;
4/124 × 100 ≈ 3.2258%
The percentage of children living in Singapore with myopia is given as follows;
183/628 × 100 ≈ 29.14%
b. The data for the time spent reading and writing is presented as follows;
Number of children [tex]{}[/tex] Mean Standard deviation
Australia 109 [tex]{}[/tex] 20.8 13.9
Singapore [tex]{}[/tex] 611 17.8 8.8
The data for the time spent outdoors is presented as follows;
Number of children [tex]{}[/tex] Mean Standard deviation
Australia 102 [tex]{}[/tex] 13.75 1.02
Singapore [tex]{}[/tex] 586 3.05 0.12
From the data, more children in Australia spend more time reading and writing and also outdoors than children in Singapore
c. From the data, more children spend their time reading and writing in Australia and are also less likely to develop myopia than children in Singapore
Therefore, the study does not suggest that more time spent reading or writing is associated with a greater risk of myopia among the enrolled children
Similarly, the study does not suggests that more time spent outdoors is associated with a greater risk of myopia
d. The advantage of collecting data from children with the same ethnicity compared with selecting random samples of children from each location regardless of ethnicity is to reduce the variables or influential factors that may alter the impact on the test and the results
The total surface area is _ square centimeters
Answer:
180 square inches
Step-by-step explanation:
First off since the square will be easiest to do
a=a^2
a=6^2
a=36
now for the triangles
a= height of triangle * base/ 2
a= 12*6/2
a= 36
and since there is 4 of the triangles we multiply 36 by 4
=144
now we add 144 to 36 and we have the total
An African elephant weighs 2 tons. How many pounds are in a herd with 26 elephants?
Answer:
52 pounds
Step-by-step explanation:
2 x 26= 52
Need help asap!!!! By 1 pm
Answer: x4
Step-by-step explanation:
s
31
T
114°
R
U
v
In the figure above, RT = TU. What is
the value of x ?
A) 72
B) 66
C) 64
D) 58
Answer:
c 64 is your answer im pretty sure