In a random sample of seven aerospace engineers, the sample mean monthly income is $6824 and the sample standard deviation is $340. Construct a 95% confidence interval for the population mean. Assume that the monthly incomes are normally distributed.
Answer:
The 95% confidence interval for the population mean is ($6510, $7138).
Step-by-step explanation:
We have the standard deviation for the sample, which means that the t-distribution is used to solve this question.
The first step to solve this problem is finding how many degrees of freedom,which is the sample size subtracted by 1. So
df = 7 - 1 = 6
95% confidence interval
Now, we have to find a value of T, which is found looking at the t table, with 6 degrees of freedom(y-axis) and a confidence level of [tex]1 - \frac{1 - 0.95}{2} = 0.975[/tex]. So we have T = 2.4469.
The margin of error is:
[tex]M = T\frac{s}{\sqrt{n}} = 2.4469\frac{340}{\sqrt{7}} = 314[/tex]
In which s is the standard deviation of the sample and n is the size of the sample.
The lower end of the interval is the sample mean subtracted by M. So it is 6824 - 314 = $6510.
The upper end of the interval is the sample mean added to M. So it is 6824 + 314 = $7138.
The 95% confidence interval for the population mean is ($6510, $7138).
OMG!! I’m stuck on 4a) b) c)
Help please
Answer:
a) 750 cmb) 288 cmc) 2112 cmStep-by-step explanation:
Formula for getting the surface area of a rectangular prism: SA = 2 (WL + HL + HW)a) SA = 2 (WL + HL + HW) = 2(75) + 2(225) + 2(75) = 150 + 450 + 150 = 750 cm^2b) SA = 2 (WL + HL + HW)= 2(48) + 2(72) + 2(24)= 96 + 144 + 48=288 cm^2c) SA = 2 (WL + HL + HW)= 2(400) + 2(400) + 2(256)= 800 + 800 + 512= 2112 cm^2[tex]\tt{ \green{P} \orange{s} \red{y} \blue{x} \pink{c} \purple{h} \green{i} e}[/tex]
Answer:
Below in bold.
Step-by-step explanation:
(a) The surface area consists of the sum of the area of 3 sets of 2 congruent rectangles. The 2 rectangles are on opposite sides of the solid.
= 2(15*15) + 2(5*15) + 2(5&15)
= 450 + 150 + 150
= 750 unit^2.
(b). Similarly to the above:
Surface area = 2(12*6) + 2(4*12) + 2(4*6)
= 144 + 96 + 48
= 288 unit^2.
(c) Again:
Surface area = 2(25*16) + 2(25*16) + 2(16*16)
= 400 + 400 + 256
= 1056 unit^2.
what is the value of k
Answer:
(A)
Step-by-step explanation:
M=-2
therefore
x¹=3, y¹=-12, x²=6 y²=k
M=(y²-y¹)/(x²-x¹)
-2=(k+12)/(6-3)
-2×3=k+12
-6=k+12
k=-18
Using the order of operations, what is the last calculation that should be done to evaluate 4(8 - 6952 - 6+(-3)
4(8 - 6352 – 6 + (-3)
4(2)52 - 6+(-3)
4(2)(25) - 6+(-3)
200 - 6+(-3)
200 - (-2)
Answer:
200 + 2
Step-by-step explanation:
you know that two (2) negatives multiplying each other is = +
=200 +2
=202
(-4/9)*3×(-27/20)*4=
(-4/9)*3×(-27/20)*4= 7.2
Step-by-step explanation:
here's the answer to your question
½ sejam berapa minit?
Answer:
1/2 jam 30 menit mungkin?
1/2 jam adalah 30 minit
1/2 × 60 = 30 mins
English translation
1/2 an hour is 30 minutes
1/2 × 60 = 30 mins
Answered by Gauthmath must click thanks and mark brainliest
It is claimed that the average child has no time to go to school. For the child spends 8 hours per day,or one third of his/her time sleeping. Based on a 365 day year, that’s 121.67days sleeping. Also the child spends three hours per day eating. That’s a total of 45 days in the year spent eating. Also the child spends 90 days taking summer vacation. Also the child spends 21 days on Christmas and Easter holiday. Finally, the child has each Saturday and Sunday off. That’s a total of 104 days. In short, we (rounding to whole days accounted for 122+45+90+21+104=382 days of the year taken up by ordinary child inlike activities. This is already more than the 365 days that are known to comprise a year. We conclude that there is certainly no time for the child to attend school. What is wrong with this reasoning?
Answer:
See below.
Step-by-step explanation:
Sleeping:
8/24 * 365 = 121.76 days
Eating:
3/24 * 365 = 45.63 days
Total sleeping and eating: 167 days
Summer Vacation & Holidays:
90 + 21 = 111 days
Saturdays and Sundays: 52 + 52 = 104 days
Vacation + Holidays Saturdays + Sundays = 111 + 104 = 215 days
It may be true that all days of vacation, holiday, Saturdays, and Sundays combined are a total of 215 days, but these 215 days cannot be added to the 167 days above because these 215 days include time for sleeping and eating which was already included in the sleeping and eating times for the entire year. The mistake in the reasoning is counting twice the time of sleeping and eating on the 215 days in which there is no school.
A common inhabitant of human intestines is the bacterium Escherichia coli, named after the German pediatrician Theodor Escherich, who identified it in 1885. A cell of this bacterium in a nutrient-broth medium divides into two cells every 20 minutes. The initial population of a culture is 50 cells.
Required:
a. Find the relative growth rate.
b. Find an expression for the number of cells after t hours.
c. Find the rate of growth after 6 hours. (Round your answer to the nearest integer.)
d. Find the number of cells after 6 hours.
Answer:
a. Relative Growth rate = 10% (6/60 * 100)
b. Number of cells after t hours = 50 * 1.1^t
c. Rate of growth after 6 hours = 77.2% (1.1⁶ - 1)
d. The number of cells after 6 hours is
= 89 cells
Step-by-step explanation:
A cell divides into two cells every 20 minutes
In one hour, the cell will divide into 60/20 * 2 = 6 cells
Each cell growth 6 cells per hour
Initial population of a culture = 50 cells
t = time in hours
a. Relative Growth rate = 10% (6/60 * 100)
b. Number of cells after t hours = 50 * 1.1^t
c. Rate of growth after 6 hours = 77.2% (1.1⁶ - 1)
d. The number of cells after 6 hours = initial population * growth factor
= 50 * 1.772
= 88.6
= 89 cells
a car completes a journey in 8hours it covers half the distance at 40kms per hours and the rest at 60 km per hour. what is the total distance of the journey?
Answer:
384 kmph
Step-by-step explanation:
Pls help
Q.2 Choose the correct alternative for each question.
1. 400 is successor of ______.
A. 399 B.401 C. 398 D. 402
(1 Marks each)
2. The product of a non-zero whole number and its predecessor is always_________.
A. an odd number B. an even numberC. 0 D. a prime number
KHALSA LITTLE FLOWER SCHOOL | GRADE 6 | Mathematics 1
3. The predecessor of 1 million is ___________.
A. 99999 B. 1000001 C. 2000000 D. 999999
4. Whole numbers are closed under ________.
A. addition and subtraction B. addition and multiplication C. addition and division D. subtraction and division
5. The only whole number which does not have a predecessor is ________. A.2 B.0 C.3 D.1
6. ________ million make 1 crore.
A. 100 B. 10 C. 1000 D. 10,000
7. 3856 is rounded off to the nearest tens as ______.
A. 3850 B. 3860 C. 3800 D. 3000 8. In Roman numerals, the symbol ______ can be repeated.
A. D B. V C. X D. L
9. The Roman numeral for 91 is _______.
A. IXLL B. CXI C. IXC D. XCI
10. The Roman numeral LV stands for _______.
A. 65 B. 45 C. 55 D. 105
Answer:
Step-by-step explanation:
1-399
2 C
3-A 99999
4a
5b
7 b
8 C
9D
10c
the incenter of a triangle is formed by the intersection of the of a triangle
Answer:
angle bisectors
Step-by-step explanation:
The incentre is where a triangle's three angle bisectors intersect ( an angle bisector is a ray that cuts an angle in half ). The incentre is the centre of a triangle drawn inside the triangle.
Kevin's supervisor, Jill, has asked for an update on today's sales, Jill is pretty busy moving back and forth between different store locations. How can Kevin most effectively deliver an update to her ? a) Call with a quick update Ob ) Send a detailed text message c ) Book a one-hour meeting for tomorrow morning d) Send a detailed email
Each marble bag sold by Debra's Marble Company contains 8 yellow marbles for every 4 blue marbles. If a bag has 56 yellow marbles, how many blue marbles does it contain?
Answer:
28 blue marbles
Step-by-step explanation:
yellow: blue
8 4
To get to 56 yellow marbles multiply by 7
yellow: blue
8*7 4*7
56 28
There will be 28 blue marbles
The distance between point (3,0) and (7, 2p) is √80. Find the value of p.
Distance = √[ ( 7 - 3 )^2 + ( 2p - 0 )^2 ]
Distance = √(4)^2 + ( 2p)^2
Distance = √16 + 4p^2
As the question said : Distance = √80
√80 = √16 + 4p^2
Thus :
16 + 4p^2 = 80
Subtract both sides 16
16 - 16 + 4p^2 = 80 - 16
4p^2 = 64
Divide both sides by 4
4p^2 ÷ 4 = 64 ÷ 4
p^2 = 16
Thus :
p = 4 or p = - 4
A certain test preparation course is designed to help students improve their scores on the LSAT exam. A mock exam is given at the beginning and end of the course to determine the effectiveness of the course. The following measurements are the net change in 5 students' scores on the exam after completing the course: 16, 21, 22, 12, 22
Using these data, construct a 90% confidence interval for the average net change in a student's score after completing the course. Assume the population is approximately normal. Find the critical value that should be used in constructing the confidence interval. Round your answer to three decimal places.
Answer:
The critical value used is [tex]T_c = 2.132[/tex]
The 90% confidence interval for the average net change in a student's score after completing the course is (14.357, 22.843).
Step-by-step explanation:
Before building the confidence interval, we need to find the sample mean and the sample standard deviation.
Sample mean:
[tex]\overline{x} = \frac{16+21+22+12+22}{5} = 18.6[/tex]
Sample standard deviation:
[tex]s = \sqrt{\frac{(16-18.6)^2+(21-18.6)^2+(22-18.6)^2+(12-18.6)^2+(22-18.6)^2}{4}} = 4.45[/tex]
Confidence interval:
We have the standard deviation for the sample, so the t-distribution is used to solve this question.
The first step to solve this problem is finding how many degrees of freedom,which is the sample size subtracted by 1. So
df = 5 - 1 = 4
90% confidence interval
Now, we have to find a value of T, which is found looking at the t table, with 4 degrees of freedom(y-axis) and a confidence level of [tex]1 - \frac{1 - 0.9}{2} = 0.95[/tex]. So we have T = 2.132. The critical value used is [tex]T_c = 2.132[/tex]
The margin of error is:
[tex]M = T\frac{s}{\sqrt{n}} = 2.132\frac{4.45}{\sqrt{5}} = 4.243[/tex]
In which s is the standard deviation of the sample and n is the size of the sample.
The lower end of the interval is the sample mean subtracted by M. So it is 18.6 - 4.243 = 14.357
The upper end of the interval is the sample mean added to M. So it is 18.6 + 4.243 = 22.843.
The 90% confidence interval for the average net change in a student's score after completing the course is (14.357, 22.843).
Classify the following data. Indicate whether the data is qualitative or quantitative, indicate whether the data is discrete, continuous, or neither, and indicate the level of measurement for the data.
A supervisor must give a summary evaluation rating from among the choices given below:
1) Poor
2) Fair
3) Good
4) Very good
5) Excellent
a. Are these data qualitative or quantitative?
b. Are these data discrete or continuous?
c. What is the highest level of measurement the data possesses?
Answer:
Qualitative data
Neither discrete or continous
Ordinal
Step-by-step explanation:
Qualitative data simply refers to Non-numeric measure, they make use of data labels which are expressed in words rather than figures or numbers.
For a data to be either discrete or continous, then it has to be numeric, since the data is qualitative and non- numeric, then it is neither continous or discrete.
This is an ordinal scale representation of data as data are ordered or ranked in terms of performance, however, there is no measure of difference between each rank or order. The highest level of performance in the scale is Excellent.
b) An achievement test was administered to a class of 20,000 students. The mean score was 80 and the standard deviation was 11. If Lingard scored 72 in the test, how many students did better than him
Answer: 15328
Step-by-step explanation:
The following can be deduced from the information given:
N = 20000
μ = 80
σ = 11
P(X>72) = 1 - P (X<72)
= 1 - P(Z < 72-80/11)
= 1 - P(Z < -8/11)
= 1 - P(Z < 0.7272)
= 1 - 0.2336 = 0.7664
Therefore, the number of students that were better than Lingard n(X > 72) will be:
= 20000 × 0.7664
= 15328
Help me please and thank you
Step-by-step explanation:
jlejej
are u using chrome os
What is the mean of 86, 80, and 95
87 is the mean.
To find the mean, you must
- add all of the numbers
- divide by the amount of numbers given
In this case, you would want to do (86 + 80 + 95)/3. This would give you an answer of 87.
Y<3/2•x-4
Match the equation to a graph.
Answer:
Last option
Step-by-step explanation:
The slope 3/2 determines the line (although you can plot points to find (0,-4) and (4,2), connecting them, you'll get the equation of the line, and the area it covers will be to the right side, putting x = 0, y<-4, which is below the line, that's how you determine it.
Answered by GAUTHMATH
Dean Halverson recently read that full-time college students study 20 hours each week. She decides to do a study at her university to see if there is evidence that students study an average of more than 20 hours each week. A random sample of 35 students were asked to keep a diary of their activities over a period of several weeks. It was found that the average number of hours that the 35 students studied each week was 21.1 hours. The sample standard deviation of 4.3 hours.
Find the p-value.
The p-value should be rounded to 4-decimal places.
Answer:
0.0698
Step-by-step explanation:
Given :
Population mean, μ = 20
Sample mean, xbar = 21.1
Sample standard deviation, s = 4.3
Sample size, n = 35
The hypothesis :
H0 : μ = 20
H0 : μ > 20
The test statistic :
(xbar - μ) ÷ (s/√(n))
T = (21.1 - 20) ÷ (4.3/√(35))
T = 1.1 ÷ 0.7268326
Test statistic = 1.513
Using the Pvalue calculator :
df = n - 1 = 35 - 1 = 34
Pvalue(1.513, 34) = 0.06976
Pvalue = 0.0698 (4 decimal places)
The p-value is 0.0698 if rounded to 4-decimal places.
It is given that students study an average of more than 20 hours each week and the random sample of 35 students was asked to keep a diary of their activities over a period of several weeks.
The average number of hours that the 35 students was 21.1 hours.
The sample standard deviation is 4.3 hours.
It is required to find the p-value.
What is the standard deviation?It is defined as the measure of data dispersement, It gives an idea about how much is the data spread out.
We can test the hypothesis using the Z test, the formula for the Z-test is given below:
[tex]\rm Z= \frac{(x-u)}{\frac{S}{\sqrt{n} } }[/tex]
Where x is the sample mean
u is the population mean
s is the standard deviation
n is the sample size.
The hypothesis are: H0 : μ = 20 V/s H1 : μ > 20
We have x = 21.1
u = 20
s = 4.3
n = 35
Putting these values in the above formula, we get:
[tex]\rm Z= \frac{(21.1-20)}{\frac{4.3}{\sqrt{35} } }\\\\\rm Z= \frac{(1.1)}{\frac{4.3}{\sqrt{35} } }\\\\[/tex]
Z = 1.513
difference or df = n -1 ⇒ 35-1 ⇒ 34
P-value at (1.513, 34) = 0.06976 (From the p-value calculator)
P-value = 0.0698 (Rounded to 4-decimal places)
Thus, the p-value is 0.0698 if rounded to 4-decimal places.
Learn more about the standard deviation here:
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Which of the following is equivalent to 5 + 5x > 8(x-1) ?
-3x > -12
3x 13
3x < 6
-4X > -12
5+5x>8(x-1)
5+5x>8x-8
5x-8x>-8+5
-3x>-3
5 + 5x > 8(x-1) is equivalent to -3x > -13.
How to estimate the equivalent function to 5 + 5x > 8(x-1) ?Let, the expression be 5 + 5x > 8(x-1)
By applying Multiplicative Distribution Law, we get
5 + 5x > 8x - 8
Rearrange unknown terms to the left side of the equation, then
5x - 8x > -8 - 5
Combine like terms, we get
-3x > -8 - 5
Calculate the sum or difference
-3x > -13
Divide both sides of the inequality by the coefficient of the variable, then we get
[tex]$x < \frac{-13}{-3}$[/tex]
Determine the sign for multiplication or division:
[tex]$x < \frac{13}{3}$[/tex]
Therefore, the correct answer is -3x > -13.
Complete question:
Which of the following is equivalent to 5 + 5x > 8(x - 1)?
-3x > -12
3x < 13
3x < 6
-4x > -12
To learn more about algebraic expression
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A box contains orange balls and green The number of more four the number of orange If there 38 balls how many green balls and how balls are there in the box ?
let number of green balls= x
let number of orange balls=x+4
x+x+4=38
2x=38-4
2x=34
x=17
number of green balls=17
number of orange balls=21
Which shows the image of rectangle ABCD after the rotation () (W)?
13
VA
1
V
Answer:
Graph (1)
Step-by-step explanation:
Given rule for the rotation of a figure is,
A(x, y) → A'(-y, x)
This rule defines the rotation of point A by 90° counterclockwise about the origin.
Coordinates of point A → (-2, 0)
Coordinates of point C → (-1, 0)
Following the rule of rotation,
A(x, y) → A'(-y, x)
A(-2, 0) → A'(0, -2)
C(-1, 4) → C'(-4, -1)
Now search the image points from the graphs attached,
Graph (1) will be the answer.
The length of a rectangle is 5 ft less than three times the width, and the area of the rectangle is 28 ft^2. Find the dimensions of the rectangle.
Answer:
7 x 4
Step-by-step explanation:
Let the width be x, length will be 3x-5. ATQ, x(3x-5)=28. x=4 and x=-7/3, since length isn't negative, x=4. Width=4 and length=7
Plz this is due today help me explain the answer
Answer:
177.3 feet
This is a classic find the vertex of a parabola question.
if this was a calculus class the solution would be to take the derivative and set it equal to zero... -32t+ 105 = 0
BUT i assume that you are not in a calculus class..
so we try plan "B" the highest (or lowest) point of parabola is it's vertex
the vertex formula is [-b/2a,f(-b/2a)]
in your problem a = -16, b=105, c= 5
so the "X" (TIME) is located at -(105)/(2*-16) = 3.28
plug in 3.28 into -16(3.28)^2 + 105(3.28) + 5 = 177.27
and you will get
Step-by-step explanation:
Two ice cream stands are deciding where to set up along a 1-mile-long beach. The people are uniformly located along the beach, and each person sitting on the beach buys exactly 1 ice cream cone per day from the nearest stand. Each ice cream seller wants the maximum number of customers. True or False: The two stands will most likely be 1/3 mile away from each other. True
Answer:
Each ice cream seller wants the maximum number of customers:
True
The two ice cream stands will most likely be 1/3 mile away from each other.
True
Step-by-step explanation:
This distance enables the two ice cream stands to give access to the maximum number of customers at the beach, which will be almost equal at their right-hand and left-hand sides. Therefore, the two ice cream stands will most likely be 1/3 mile away from each other. Such positioning exposes the ice cream stands to almost equal number of customers since the people standing along the beach are uniformly located. Taking the extreme locations along the 1-mile-long beach will shrink location opportunities for both stands.
solve for x
8x2-5=11
Answer:
1
Explainion show in picture above
Answer:
x=6
Step-by-step explanation:
It should be 8+x+2-5=11
h is a trigonometric function of the form h(x)=a sin(bx+c)+d. Below is the graph h(x). The function intersects its midline at (-pi,-8) and has a maximum point at (pi/4, "-1.5)." Find a formula for h(x). Give an exact expression.
Answer:
6.5sin(.04x+.4pi)-8
The function intersects its midline at (-pi,-8) and has a maximum point at (pi/4, "-1.5). The final equation is h(x) = 4 sin(2x + π /2) + 3.
What is a function?A function is defined as a relation between the set of inputs having exactly one output each.
The function intersects its midline at (3π/4, 3) then the midline is d= 3.
The amplitude is just the positive distance between the maximum/minimum and the midline,
so the amplitude a = 7 - 3 = 4
Also, given that period is 2π/b and the fact that the period is π from our given maximum,
we have the equation 2π/b= π where b = 2
we know that the phase shift, -c/b is - π/4 (or to the left)
since -π /4. Therefore, c = π /2.
our final equation is
h(x) = 4 sin(2x + π /2) + 3.
Learn more about function;
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Which matrix equation represents the system of equations?
Answer:
B. [tex]\left[\begin{array}{ccc}-1&2\\0&1\\\end{array}\right] \left[\begin{array}{ccc}x\\y\\\end{array}\right] =\left[\begin{array}{ccc}0\\-2\\\end{array}\right][/tex]
Step-by-step explanation:
Given the systems of equations
-x + 2y = 0
y = -2
This can also be written as:
-x + 2y = 0
0x + y = -2
We are to write in this form AX = b
A is a 2by2 matrix with coefficients of x nd y
X is a column matrix containing the unknown
b is a column matrix with the values at the right hand sides (0 and -2)
Writing in matrix form;
[tex]\left[\begin{array}{ccc}-1&2\\0&1\\\end{array}\right] \left[\begin{array}{ccc}x\\y\\\end{array}\right] =\left[\begin{array}{ccc}0\\-2\\\end{array}\right][/tex]
