Answer:
The answer is a
Step-by-step explanation:
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Determine the intervals where the value of f(x) is positive, when f(x)= (x + 7)(2x + 3)(x + 5). Choose all that apply
a. -∞ < x < 7
b. -7 < x < -5
c. -5 < x < -3/2
d. -3/2 < x < ∞
Answer:
b and dStep-by-step explanation:
Find zero's:
x = -7x = -3/2x = -5The intervals:
x < -7, all negative, the result is negativex is between -7 and -5, two negatives, the result is positivex is between -5 and -3/2, one negative, the result is negativex is greater than -3/2, all 3 positives, the result is positiveAs we see correct choices are b and d
The average breaking strength of a certain brand of steel cable is 2000 pounds, with a standard deviation of 100 pounds. A sample of 20 cables is selected and tested. Find the sample mean that will cut off the upper 95% of all samples of size 20 taken from the population. Assume the variable is normally distributed.
Answer:
The sample mean that will cut off the upper 95% of all samples of size 20 taken from the population is of 1963.2 pounds.
Step-by-step explanation:
To solve this question, we need to understand the normal probability distribution and the central limit theorem.
Normal Probability Distribution
Problems of normal distributions can be solved using the z-score formula.
In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the z-score of a measure X is given by:
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.
Central Limit Theorem
The Central Limit Theorem establishes 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.
The average breaking strength of a certain brand of steel cable is 2000 pounds, with a standard deviation of 100 pounds.
This means that [tex]\mu = 2000, \sigma = 100[/tex]
A sample of 20 cables is selected and tested.
This means that [tex]n = 20, s = \frac{100}{\sqrt{20}} = 22.361[/tex]
Find the sample mean that will cut off the upper 95% of all samples of size 20 taken from the population.
This is the 100 - 95 = 5th percentile, which is X when Z has a p-value of 0.05, so X when Z = -1.645. So
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
By the Central Limit Theorem
[tex]Z = \frac{X - \mu}{s}[/tex]
[tex]-1.645 = \frac{X - 2000}{22.361}[/tex]
[tex]X - 2000 = -1.645*22.361[/tex]
[tex]X = 1963.2[/tex]
The sample mean that will cut off the upper 95% of all samples of size 20 taken from the population is of 1963.2 pounds.
find the measure of the angle
Answer: 86
Step-by-step explanation:
This is a cyclic quadilateral in which opposite angles adds upto 180.
Let the unknown angle be x
ATQ
x + 94 = 180
x = 180 - 94
x = 86
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Find f(-1) given f(x) = –2x^3 + 3x^2 – 22
[tex]\\ \sf\longmapsto f(-1)[/tex]
[tex]\\ \sf\longmapsto -2x^3+3x^2-22[/tex]
[tex]\\ \sf\longmapsto -2(-1)^3+3(-1)^2-22[/tex]
[tex]\\ \sf\longmapsto -2(-1)+3(1)-22[/tex]
[tex]\\ \sf\longmapsto 2+3-22[/tex]
[tex]\\ \sf\longmapsto 5-22[/tex]
[tex]\\ \sf\longmapsto -17[/tex]
A researcher wants to better understand the health benefits of eating vegetables. In a study he finds 300 adults aged 45-60 who eat at least 3 servings of vegetables a day on average. He finds another 200 adults who eat less than 3 servings of vegetables a day on average. The researcher looks at rates of cancer and heart disease in each group and compares both groups. In another study, the researcher finds 500 adults aged 45-60 who eat less than 3 servings of vegetables a day on average, and are willing to participate in a study. The researcher randomly assigns 250 of these adults to a diet which includes 4 servings of vegetables a day. The other 250 continue their usual habits. After 4 years, the rates of cancer and heart disease between the two groups are compared
Identify the statement that correctly states the reason for considering the first study as an observational study and second study as an experiment.
a. In the first study, the treatment is not imposed on the subjects, whereas in the second study the treatment is imposed on the subjects.
b. In the first study, the treatment is not imposed on every subject, whereas in the second study the treatment is imposed on every subject.
c. In the first study, the subjects were not randomly chosen, whereas in the second study the subjects were randomly assigned.
Answer:
a. In first study, the treatment is not imposed on the subjects, whereas in the second study the treatment is imposed on subjects.
Step-by-step explanation:
In the first study, observation are made on 300 adults who eat 3 servings of vegetables a day on average. The second study has further intensified the research which imposed treatment on the subjects. The random samples of adults are observed in both studies.
What is the equation of a horizontal line passing through the point (-7,5)?
Oy = 5
Oy = -7
Ox=5
Ox= - 7
Answer:
1st option, y = 5
Step-by-step explanation:
when the line is horizontal, it's parallel to the x axis
Answer:
y = 5
Step-by-step explanation:
The equation of a horizontal line parallel to the x- axis is
y = c
where c is the value of the y- coordinates the line passes through
The line passes through (- 7, 5 ) with y- coordinate 5 , then
y = 5 ← is the equation of the line
Last year, Rob set up the Road Runner Race for his school.
The race was 1,200 meters long and 188 people signed up to
run the race. 38 people did not show up to run. This year,
there will be 3 times as many runners as last year. How
many people will run the race this year?
Answer:
450 runners
Step-by-step explanation:
Clifford is paid $4.25 per hour plus time and a half on holidays and makes an average of 21% tips on his food sales as a server at the local seafood restaurant. This is modeled by the expression 4.25(x) + 4.25(1.5)(y) + 0.21(z). What is Clifford's gross pay if he worked 15 regular hours and 7 holiday hours and had $1,345 in food sales? (2 points)
$356.83
$390.83
$422.70
Which ordered pair is a solution to the system of inequalities? y > 2x
y > 7
A. (0, 0) B. (4, 8) C. (3, 7) D. (1, 9)
Answer:
D( 1,9)
Step-by-step explanation:
First y must be greater than 7 which eliminates A and C
y must be greater than 2 times the x value
2*4 = 8 so B is eliminated
2*1 = 2 which is less than 9 Choice D is a solution
What is the standard deviation?
8, 10, 12,14,16,18,20
PLEASE show work
Answer:
4
Step-by-step explanation:
The given data is :
8, 10, 12,14,16,18,20
We need to find the standard deviation. Here,
Count = 7
Sum, Σx: 98
Mean, μ: 14
The standard deviation is given by :
[tex]\sigma=\sqrt{\dfrac{1}{N}\Sigma(x_i-\mu)^2}[/tex]
or
[tex]\sigma^2=\dfrac{1}{N}\Sigma(x_i-\mu)^2\\\\=\dfrac{(8-14)^2+...+(20-14)^2}{7}\\\\=\dfrac{112}{7}\\\\\sigma^2=16\\\\\sigma=4[/tex]
So, the standard deviation of the given data is 4.
The product of x and its opposite is always 1.
O True
O False
Answer:
False
Step-by-step explanation:
x
The opposite of x is -x
x* -x = -x^2
This is not always 1
Answer:
false
Step-by-step explanation:
x*-x= - x ² so its not always 1
so I just started using brainly sorry if its not appropriate
(B) An airline knows from experience that the distribution of the number of suitcases that get lost each week on a certain route is normal with μ (mean) = 15.5 and σ (standard deviation) = 3.6. What is the probability that during a given week the airline will lose between 11 and 19 suitcases?
Answer:
The correct answer is "0.7289".
Step-by-step explanation:
The given values are:
Mean,
[tex]\mu = 15.5[/tex]
Standard deviation,
[tex]\sigma = 3.6[/tex]
As we know,
⇒ [tex]z = \frac{(x - \mu)}{\sigma}[/tex]
The probability will be:
⇒ [tex]P(11< x< 19) = P(\frac{11-15.5}{3.6} <z<\frac{19-15.5}{3.6})[/tex]
[tex]=P(z< 0.9722)-P(z< -1.25)[/tex]
By using the z table, we get
[tex]=0.8345-0.1056[/tex]
[tex]=0.7289[/tex]
Determine the maturity value of a 45-day note for $1,250 dated May 23 and bearing interest 8%.
The maturity value of a 45-day note for $1,250 dated May 23 and bearing interest 8% is $1,262.5
Using this formula
Maturity value=Principal amount+ Interest
Let plug in the formula
Maturity value=$1,250+($1,250*8%*45 days/360 days)
Maturity value=$1,250+$12.5
Maturity value=$1,262.5
Inconclusion the maturity value is $1,262.5
Learn more about maturity value here:
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The Rogers family and the Brooks family each used their sprinklers last summer. The Rogers family's sprinkler was used for 30 hours. The Brooks family's sprinkler was used for 25 hours. There was a combined total output of 1775 L of water. What was the water output rate for each sprinkler if the sum of the two rates was 65 L per hour?
Step-by-step explanation:
what happens if there is excess or deficit of proteins in our body
The difference between two positive integers is 3. If the smaller is added to the square of the larger, the sum is 129.
Step 2 of 2 : Find the integers by solving the equation.
Answer:
11 and 8
Step-by-step explanation:
Let the integers be x and y. ATQ y-x=3 and x+y^2=129. Solving it, we will get x=8 and y=11
Need helpppp ! tyyy
Answer:
63°
Step-by-step explanation:
Both angle 3 and 2 are equal because of the property of vertically opposite angles.What is the measure of b, in degrees
Answer:
B) 32
Step-by-step explanation:
(sin 74) / 10 = (sin c) / 10
c = 74
180 - 74 -74
= 32
1. Find the volume of a rectangular block 15 cm long, 5 cm wide and 10 cm length
9514 1404 393
Answer:
750 cm³
Step-by-step explanation:
The volume is given by the formula ...
V = LWH . . . . where L, W, H represent length, width, height
The volume is the product of the dimensions.
V = (15 cm)(5 cm)(10 cm) = 750 cm³
A group of hikers is descending a mountain at a rate of 400 feet per hour. After three hours, what integer represents their total change in elevation?
I am not sure if it's -1200 (because it said descending)
Or if it's just 1200
Answer:
Bro it will be +1200
Step-by-step explanation:
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A boat takes 3 days to travel from town A to town B, but it takes 4 days to travel from town B to town A. If a motor-less raft is left alone in the water by town A, how long will it take for the raft to float to town B?
Answer:
24 days
Step-by-step explanation:
The distance from A to B equals the distance from B to A.
Let the distance between A and B be d.
3 days = 72 hours
4 days = 96 hours
speed = distance/time
speeds are in miles per hour
speed from A to B = d/72
speed from B to A = d/96
difference in speeds:
d/72 - d/96 = d/288
The speed of the water is half of the difference.
speed = d/576
When the raft floats from A to B, it uses only the speed of the water.
d/576 / d/72 = 1/8
The speed of the water is 1/8 the overall speed of the trip from A to B, so traveling by the speed of the water alone must take 8 times longer than with the boat motor.
8 * 3 days = 24 days
Find the dimensions of a rectangle with perimeter 108 m whose area is as large as possible. (If both values are the same number, enter it into both blanks.) m (smaller value) m (larger value)
Answer:
27 by 27
Step-by-step explanation:
Let the sides be x and y. The problem is essentially asking:
Given 2(x+y)=108, maximize xy.
We know that x+y=54. By the Arithmetic Mean - Geometric Mean inequality, we can see that [tex]\frac{x+y}{2} \ge \sqrt{xy[/tex]. Substituting in x+y=54, we get [tex]27\ge\sqrt{xy}[/tex], meaning that [tex]729 \ge xy[/tex]. Equality will only be obtained when x=y (in this case it will generate the maximum for xy), so setting x = y, we can see that x = y = 27. Hence, 27 is the answer you are looking for.
The scores of a high school entrance exam are approximately normally distributed with a given mean Mu = 82.4 and standard deviation Sigma = 3.3. What percentage of the scores are between 75.8 and 89?
Notice that
75.8 = 82.4 - 6.6 = 82.4 - 2 × 3.3
89 = 82.4 + 6.6 = 82.4 + 2 × 3.3
Then the percentage of students with scores between 75.8 and 89 make up the part of the distribution that lies within 2 standard deviations of the mean. The empirical (68-95-99.7) rule says that approximately 95% of any distribution lies within this range.
Answer:
b
Step-by-step explanation:
Solve for x. Round to the nearest tenth, if necessary.
S
540
R
2.3
X
O
Please help
Answer:
[tex]\boxed {\boxed {\sf x \approx 1.9}}[/tex]
Step-by-step explanation:
We are asked to find x, a missing side in a triangle.
This is a right triangle because there is a small square in the corner representing a 90 degree or right angle. Therefore, we can use right triangle trigonometry. The three main functions are:
sinθ= opposite/hypotenuse cosθ= adjacent/hypotenuse tanθ= opposite/adjacentExamine the triangle. We will use angle S, measuring 54 degrees, for theta. Side QR, measuring x, is opposite angle S. Side QS, measuring 2.3, is the hypotenuse because it is opposite the right angle. Since we have the opposite and hypotenuse, we will use sine.
[tex]sin \theta = \frac {opposite}{hypotenuse}[/tex]
θ= 54opposite= x hypotenuse = 2.3[tex]sin (54)= \frac{ x}{2.3}[/tex]
We are solving for x, so we must isolate the variable. It is being divided by 2.3 The inverse operation of division is multiplication, so we multiply both sides by 2.3
[tex]2.3* sin (54)= \frac{x}{2.3}*2.3[/tex]
[tex]2.3* sin (54)=x[/tex]
[tex]2.3*0.8090169944=x[/tex]
[tex]1.860739087 =x[/tex]
Round to the nearest tenth. The 6 in the hundredth place to the right tells us to round the 8 up to a 9.
[tex]1.9 \approx x[/tex]
x is approximately 1.9
Please answer spammers will be reported
Answer:
Answer is number 2 as twice of 2 is 4 and double of 4 is 8 and 8+2=10
Step-by-step explanation:
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Plz help
Need answers ASAP
Answer:
1. cube
2. square pyramid
4. cone
5. cube
Charla has six segments with which to make two triangles. The segments lengths are 2 in., 3 in., 4 in., 5 in., 6 in., and 7 in. Which are possible side lengths of her two triangles?
2 in., 4 in., 6 in. and 3 in., 5 in., 7 in.
2 in., 5 in., 6 in. and 3 in., 4 in., 7 in.
2 in., 3 in., 4 in. and 5 in., 6 in., 7 in.
2 in., 3 in., 6 in. and 4 in., 5 in., 7 in.
Answer:
The answer is option C
2 in., 3 in., 4 in. and 5 in., 6 in., 7 in.
Step-by-step explanation:
A math professor is wondering if students today are better or worse than in the past. He has given the same final to this year's class that he gave ten years ago. Compute mean, median, and mode for both classes and write a paragraph summarizing the differences.
This Year
35 45 65 75 87
80 69 71 53 90
99 95 70 82 73
93 67 61 57 74
72 77 71 81 83
Ten Years Ago
56 77 75 76 59
74 51 89 55 79
67 77 69 91 68
90 65 79 69 79
87 86 98 91 95
Answer:
Kindly check explanation
Step-by-step explanation:
Given the following data:
This year :
35, 45, 53, 57, 61, 65, 67, 69, 70, 71, 71, 72, 73, 74, 75, 77, 80, 81, 82, 83, 87, 90, 93, 95, 99
Mean = ΣX / n = 1825 / 25 = 73
The mode = 71 ( most frequently occurring)
Median = 1/2(n+1)th term = 1/(26) = 13th term
Median = 73
10 years ago :
51, 55, 56, 59, 65, 67, 68, 69, 69, 74, 75, 76, 77, 77, 79, 79, 79, 86, 87, 89, 90, 91, 91, 95, 98
Mean = ΣX / n = 1902 / 25 = 76.08
The mode = 79 ( most frequently occurring)
Median = 1/2(n+1)th term = 1/(26) = 13th term
Median = 77
According to the computed statistics, we can conclude that, today is worse than the past as the average score which is almost similar to the median value is higher 10 years ago and the modal score is better 10 years ago as well.
1 calculate the weight of a dog on the earth and on the moon if it has a mass of 28kg
To solve the problem.
W=m×g
W=28×10
W=280.
The weight of a dog on the surface of earth is 280N.
Answer:
274.68N and 45.36N respectively
Step-by-step explanation:
Weight of any object is the mass in kilograms(kg) multiplied by the gravity in meter per square second(m/s^2). The gravity on earth is 9.81m/s^2 and on moon is 1.62m/s^2...so since the gravity varies the weight of the dog will also vary. The wight on earth would be 28kg multiplied by 9.81m/s^2 which would be 274.68N and the weight on moon would be 28kg multiplied by 1.62m/s^2 which would be 45.36N.
i need help and thx you freinds
Answer:
Below
Step-by-step explanation:
Find the areas of the triangles on the sides
A = bh / 2
= (3)(5) / 2
= 7.5
There are 2 of these so it would just be 15
Now for the square
A = lw
= (5)(6)
= 30
Add em all up
Total area = 15 + 30
= 45 cm^2
Hope this helps!
Which of the following behaviors would best describe someone who is listening and paying attention? a) Leaning toward the speaker O b) Interrupting the speaker to share their opinion c) Avoiding eye contact d) Asking questions to make sure they understand what's being said
The answer is A and D
good luck
