The times that buses arrive at bus stops in various cities and in various climates are noted by a researcher in a notebook. This study is an observational one. Here option D is the correct answer.
It is an observation because it involves systematically noting people's actions, things, and occurrences without engaging in conversation or other interactions. In observational studies, the impact of a risk factor, diagnostic test, therapy, or other intervention is observed without an attempt to alter who is or is not exposed to it.
Two categories of observational studies are cohort studies and case-control studies. It cannot be a single-blind experiment, nor can it be a double-blind experiment since it is not an experiment.
Single-blind refers to a subject or an assessor. When a study is double-blind, neither the patient nor the outcome evaluator is aware of who received the prescription. It is not a survey because it relies on interviews with a representative sample of people as the main way of gathering data.
Complete question:
A researcher writes down in a notebook the arrival times of different city buses at a bus stop during different weather conditions. Which kind of study is this?
A - observational
B - survey
C - single-blind experiment
D - double-blind experiment
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Fill in the table using this function rule.
y=3x+1
X
2
3
6
7
X
y
0
0
0
S
Answer:
y={7,10,19,22}
Step-by-step explanation:
3(2)+1 = 6+1 = 7
3(3)+1 = 9+1 = 10
3(6) + 1 = 18+1 = 19
3(7) + 1 = 21+1 = 22
if a population begins with 25 individuals and grows exponentially for 20 generations with an r value of 0.2, then the greatest percentage increase will occur: please choose the correct answer from the following choices, and then select the submit answer button. answer choices from generation 11 to 12. from generation 5 to 6. from generation 1 to 2. from generation 19 to 20.
Answer: from generation 19 to 20.
Step-by-step explanation:
The greatest percentage increase will occur from generation 19 to 20 as the exponential power will be highest.
What is exponential growth?
Exponential growth happens once the larger in size you're the quicker you grow that causes you to even larger in size. it's the expansion characterised by interest, or growth. it's known as exponential growth as a result of it will solely be delineate mathematically by inserting time within the exponent or power of the bottom. Population then is adequate to the population at the current times some discretional range to the facility of the expansion rate times the time. The discretional range is sometimes two then the expansion rates is given because the reciprocal of the doubling time.
Main body:
initial population = 25
Total generation = 20
growth rate = 0.2
General formula of exponential function = aˣ
here a = 25 and x = 0.2
⇒25⁰°²
= 1.9
hence total population = 25+2 = 27
So it is clear that in 19 to 20 generation , growth will be highest.
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1. A local zoo had 750 visitors on Saturday. If
20% of the guests traveled from out of town,
how many local guests visited the zoo on
Saturday?
The percentage is calculated by dividing the required value by the total value and multiplying by 100.
Required percentage value = a
total value = b
Percentage = a/b x 100
The number of local guests who visited the zoo is 600.
What is a percentage?
The percentage is calculated by dividing the required value by the total value and multiplying by 100.
Example:
Required percentage value = a
total value = b
Percentage = a/b x 100
Example:
50% = 50/100 = 1/2
25% = 25/100 = 1/4
20% = 20/100 = 1/5
10% = 10/100 = 1/10
We have,
Total number of visitors = 750
The percentage that visited the zoo.
= 100% - 20%
= 80%
Now,
The number of local guests who visited the zoo.
= 80% of 750
= 80/100 x 750
= 600
Thus,
The number of local guests who visited the zoo is 600.
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5 years ago muskam was twice as old as sesay .if the sum of their ages is 100 find sesay present age
The present age of Sesay is found as the 35 years.
Explain the term twice of the number?The term "twice" simply implies "multiply by two." Typically, when working with numbers in algebra, we don't know their values; instead, we only refer to them as variables and express them with letters. The quantity in question in this instance is x. Similar to how twice 3 is written as 23,For the stated question;
Let the age of Sesay five years ago be 'x'.
Then, the age of Muskam is twice of Sesay be '2x'.
The sum of their present ages after 5 years is;
(x + 5) + (2x + 5) = 100
3x + 10 = 100
3x = 90
x = 30 (Age of Sesay 5 years ago)
Present age of Sesay = x + 5 = 30 + 5 = 35 years.
Thus, the present age of Sesay is found as the 35 years.
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576,000 in science notation
Answer: 5.76 x 10 to the 5th
What is the equation of a line that has a
3/4
slope of and an x-intercept of 0?
A y=0
B y=3/4
C y=3/4x
D y=x+3/4
Answer: C
Step-by-step explanation: This is because there is no y - intercept. But since there is still a slope an x but be next to the 3/4. Which represents the rate of change.
Ernesto guesses there are 69 marbles in a jar, but there are actually 60.
What is the percent error in Ernesto's guess?
Answer:
15%
Step-by-step explanation:
Since the problem is to find how much 69 is as a percent if 60 is 100%, we can use a rule of three, simple, direct proportion to do it:
60 = 100%
68 = x
x = 69x100/60
x = 115
That means 69 is 115% of 60, which means that the error is of:
115 - 100 = 15%
Hope this helps, have a great day! :D
A car is sold for $80, 000. Every year it loses 1/4 of its value.
a. Write an equation to represent the value of the car after 1 year.
b. Write an equation to represent the value of the car after t years.
A=P(1+ r/n)^n•t
An equation to represent the value of the car after 1 year is P(t) = 80,000(1 - 0.25)¹.
An equation to represent the value of the car after t years is P(t) = 80,000(1 - 0.25)^t.
How to write this equation?Generally speaking, a physical asset that loses its value at specific period of time represent an exponential decay. Therefore, a mathematical model for any physical asset (car) that decreases by r percent per unit of time is an exponential equation of this form:
P(t) = I(1 - r)^t
Where:
P(t ) represents the value of car in dollars.t represents the time or number of years.I represents the initial value of car.r represents the decay rate.Note: 1/4 is equal to 0.25.
For a car that loses 1/4 of its value annually, after 1 year its value is given by;
P(t) = 80,000(1 - 1/4)^1
P(t) = 80,000(1 - 0.25)¹
For a car that loses 1/4 of its value annually, after t year its value is given by;
P(t) = 80,000(1 - 0.25)^t
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Donnie, Karim, and Shawn run on the cross-country team. At yesterday’s practice, Donnie ran 200% as far as Karim. The ratio of the distance that Karim ran to the distance that Shawn ran is 4 : 3.
If you add the distance that all three boys ran, you get a sum of 45 miles. How far did each boy run individually?
this is ratio problem
The distance that each boy ran is as follows:
Donnie = 24 miles
Karim = 12miles
Shawn = 9 mile.
What is ratio?Ratio is defined as an expression that is used to represent the part of a whole entity or structure.
The total distance covered by the three boys = 46miles.
Distance covered by Donnie = 200% of Karim (ratio 4)
That is;
200/100×4 = 8
Now the ratio of the three boys = 8:4:3
To calculate the distance of each boy is by finding the total ratio of the whole boys such as:
= 8+4+3 = 15
For Donnie = 8/15×45 = 24 miles
For Karim = 4/15×45 = 12 miles
For Shawn = 3/15 × 45 = 9 miles
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5pts and who ever get this right gets brainliest
Answer:D is incorrect
Step-by-step explanation:
D is the only one that is incorrect because D is 9x-81
Answer:
(d) 9(x -9)
Step-by-step explanation:
You want the expression that is not equivalent to the other three.
Simplified expressionsThe simplified versions of the expressions are ...
9(x -1) = 9x -99x -92x -4 +7x -5 = (2+7)x +(-4 -5) = 9x -99(x -9) = 9x -81 . . . . . . . not equivalent to the othersThe expression not equivalent to the other three is 9(x -9).
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An arts academy requires there to be 4 teachers for every 72 students and 3 for every 30 students. How many students does the academy have per teacher? Per tutor? How many tutors does the academy need if it has 60 students?
1. The students that the academy have per teacher is 18.
2. The students per tutor will be 10.
3. The tutors that the academy need if it has 60 students is 6 tutors.
How to calculate the number of students?Given that the arts academy requires there to be 4 teachers for every 72 students and 3 for every 30 students.
The students that the academy have per teacher will be:
= Number if students / Teacher
= 72/4
= 18 students per teacher.
The students per tutor will be:
= 30/3
= 10 students per tutor
The number of tutors for 60 students will be:
= 60 / 10
= 6 tutors.
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What is the Factor of 30 and 45?
What is the Factor of 3 and 8?
Answer:
1. The GCF is 15 and the LCF is 1.
There are 4 common factors: 1, 3, 5, 15
2. The GCF and LCF is 1. This is the only common factor.
Step-by-step explanation:
To find common factors, think about what two numbers you can multiply to get the desired values. The numbers that are the same for both desired values are going to be factors.
I got the rest of the answers just stuck on these two
The slope for the first table will be;
⇒ m = - 4/3
The slope for the second table will be;
⇒ m = 1 / 4
What is Equation of line?
The equation of line in point-slope form passing through the points
(x₁ , y₁) and (x₂, y₂) with slope m is defined as;
⇒ y - y₁ = m (x - x₁)
Where, m = (y₂ - y₁) / (x₂ - x₁)
Given that;
There are two table is shown in figure.
Now,
For first table;
Two points are,
⇒ (x, y) = (3, -6) (0, - 2)
Since, The slope of the line passing through the points (x₁ , y₁) and
(x₂, y₂) will be;
⇒ m = (y₂ - y₁) / (x₂ - x₁)
Hence, Slope for first table;
⇒ m = (- 2 - (-6)) / (0 - 3)
⇒ m = (- 2 + 6) / (-3)
⇒ m = - 4/3
And, For second table;
Two points are,
⇒ (x, y) = (0, -3) (4, - 2)
Since, The slope of the line passing through the points (x₁ , y₁) and (x₂, y₂) will be;
⇒ m = (y₂ - y₁) / (x₂ - x₁)
Hence, Slope for second table;
⇒ m = (- 2 - (-3)) / (4 - 0)
⇒ m = (- 2 + 3) / (4)
⇒ m = 1 / 4
Thus, The slope for the first table will be;
⇒ m = - 4/3
The slope for the second table will be;
⇒ m = 1 / 4
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we want to construct a 99% confidence interval for the proportion of people who will vote 'yes' on a ballot question in the next election. how many people should we sample to construct such an interval with a margin of error of 3%?
The sample size should be 1843 at 99% confidence level with margin of error of 3%.
What is Inferential statistics?
By studying the samples that were drawn from the population data, inferential statistics aids in the development of a solid knowledge of the data. By utilising numerous analytical techniques, it aids in the creation of population-level generalisations.
Given, Margin of error (m) = 0.03
z (at 99% confidence level)=2.576
We know that, Sample size(n) = (z/m)^2 p (1-p)
In order to find the sample size, we must know the value of proportion.
here, the value of proportion is missing so, in the absence of proportion, we will consider it as 0.5.
Now, we've p = 0.5
∴ Sample size = (z/m)^2 p (1-p)
= (2.576/0.03)^2 × 0.5 × (1-0.5)
= 1843 (approx).
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What is the distance between the points (11,19) and (11,-6) in the coordinate plane?
Answer: 25 units
Step-by-step explanation:
distance with negatives is still an addition but you have to turn the negative into a positive to get the answer.
Determine which integer in the solution set will make the equation true. 8x − 4 = 2(2x + 4)
S: {−4, 0, 3, 12}
Solving the equation 8x − 4 = 2(2x + 4) the required integer to make the equation true is 3
How to find the integerThe integer required to be found is solved as follows
The given equation is 8x − 4 = 2(2x + 4)
solving for x
8x − 4 = 2(2x + 4)
8x - 4 = 4x + 8
collecting like terms
8x - 4x = 8 + 4
4x = 12
dividing through by 4
x = 3
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an srs of 28 students at uh gave an average height of 5.9 feet and a standard deviation of .1 feet. construct a 90% confidence interval for the mean height of students at uh.
The 90% confidence interval for the mean height of students at UH is (5.885,5.915) feet.
We have given that, an srs of 28 students at UH gave an average height of 5.9 feet and a standard deviation of 0.1 feet.
i.e n = 28
x = 5.9 feet
s = 0.1 feet
and we have to construct a 90% confidence interval for the mean height of students at UH.
The level of significance, α = 1 - 0.9 = 0.1
The value of 0.9 in z-table is 0.816.
The formula for confidence interval is,
CI = x ± z* (s/[tex]\sqrt{n}[/tex])
Substituting the values,
CI = 5.9 ± (0.816) (0.1/√28 )
= 5.9 ± (0.816)(0.1/5.291)
= 5.9 ± (0.816)(0.0189)
CI = 5.9 ± 0.015
CI = 5.9 + 0.015 = 5.915
CI = 5.9 - 0.015 = 5.885
Therefore 90% confidence interval for the mean height of students at UH is 5.885 feet to 5.915 feet.
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A
Given:
O HA
ZC, ZF are rt. Z's; AC= DF, BC= EF
O LA
OLL
B D.
OHL
F
E
Answer: your question is not very clear
Step-by-step explanation:
Equations with variables on both sides that equal 19
An equation with variables on both sides that equal 19 is x - 2 = 17.
What is an equation?An equation is the statement that illustrates the variables given. In this case, two or more components are taken into consideration to describe the scenario. It is vital to note that an equation is a mathematical statement which is made up of two expressions that are connected by an equal sign
Based on the information, the equation will be:
x - 2 = 17
Collect like terms
x = 17 + 2
x = 19
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What is the color red?
Answer:
red im pretty sure
what is the remainder when the positive integer n is divided by the positive integer k, where k > 1 ? (1) n
n=(K+1)^3 the remainder when the positive integer n is divided by the positive integer k, where k > 1
What is Remainder?
The value remaining after division is known as the Remainder. After division, we are left with a value if a number (dividend) cannot be divided entirely by another number (divisor). The remaining is the name for this amount.
For instance, 10 is not precisely divisible by 3. We can calculate 3 x 3 = 9 because that is the closest value.
As a result, 10 3 3 R 1, where 1 is the remainder and 3 is the quotient.
As we are aware:
Dividend: Divisor x Quotient + Remainder
Therefore,
Dividend - Remainder (Divisor x Quotient)
The formula for the remainder is as follows.
[tex]n=(k+1)^3\\\\=k^3+3k^2+3k+1\\\\=k(k^2+3k+3)+1=(k+1)^3\\\\=k^3+3k^2+3k+1=k(k2+3k+3)+1 \\\\[/tex]
[tex]k(k^2+3k+3)[/tex] is clearly divisible by k, because 1 divided by k gives 1 as the result (since k > 1).
The remainder will be n= (K+1)^3
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The sum of 4 times a number and 2 is two times the number minus 8. What is the number?
Answer:
Step-by-step explanation:
The word "Sum" = addition.
"A number" = the unknown, aka 'x'.
"Is equal to" is =.
Go piece by piece. I will set your equation exactly as it is worded as you read it. Follow along:
4x + (-2) = 5x + (-2)
Imagine there is a "1" infront of the parenthesis around the -2. A positive * a negative always = negative. So.
please help me due in 10 min
Answer: A = 2(x+3y)+2z=2z+4x+2y
B=2(x+3y)=4x+2y
c=x+3y=2x+y
d=2y=x
Step-by-step explanation:
Answer:
2y=x:D
x+3y=2x+y:C
2(x+3y)=4x+2y:B
2(x+3y)+2z=2z+4x+2y
Step-by-step explanation:
D is the only possibility for 2y=x because it has 3 total. Similarly for C. B only has two different types, so it must be 2(x+3y)=4x+2y.
In a city with an 8.5% tax rate, what would be the total cost for a $66.00
for each of the following implications, state the converse, inverse, and contrapositive. a. if a quadrilateral is a parallelogram, then its opposite sides are congruent. b. if two lines do not intersect, then they are parallel. c. if the sky does not look blue, then it is not night time. d. if a rectangle is a parallelogram, then it is not a quadrilateral.
A statement in the form p→q has three related implications that are called converse, inverse, and contrapositive.
A statement in the form p→q has three related implications.
Statement: If p then q (p→q)
Converse: If q then p (q→p)
Inverse: If not p then not q (-p → -q)
Contrapositive: If not q then not p (-q → -p)
For the given implications, its converse, inverse, and contrapositive can be written as.
Given statement:
(a) If a quadrilateral is a parallelogram, then its opposite sides are congruent then its converse, inverse, and contrapositive are:
Converse: If a quadrilateral has opposite sides that are congruent then it's a parallelogram.
Inverse: If a quadrilateral is not a parallelogram then its opposite sides are not congruent.
Contrapositive: If a quadrilateral has opposite sides that are not congruent then it's not a parallelogram.
(b) If two lines do not intersect, then they are parallel:
Converse: If the two lines do not intersect in the same plane, then they are parallel.
Contrapositive: If the two lines intersect in the same plane, then they are not parallel.
(c) If the sky does not look blue, then it is not nighttime:
Converse: If it is not nighttime, then the sky looks blue.
Inverse: If the sky does not look blue then it is nighttime.
Contrapositive: If it is nighttime then the sky does not look blue.
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Given the following: f(x)=x^2-8x+4;\;g(x)=4x+3;\;and\;h(x)=x+2.f(x)=x
2
−8x+4;g(x)=4x+3;andh(x)=x+2.
What is the result of the following: \left(\frac{\mathrm{h}}{\mathrm{g}}\right)(x)(
g
h
)(x)
The result of the following: [tex]\left(\frac{\mathrm{h}}{\mathrm{g}}\right)(x)[/tex] is (x+2)/( 4x+3).
What is an equation?An equation is an expression that shows the relationship between two or more numbers and variables.
Given the following function:
[tex]f(x)=x^2-8x+4;\;g(x)=4x+3;\;and\;h(x)=x+2.[/tex]
We need to find the result of the following: [tex]\left(\frac{\mathrm{h}}{\mathrm{g}}\right)(x)[/tex]
Therefore,
g(x)=4x+3
h(x)=x+2
[tex]\left(\frac{\mathrm{h}}{\mathrm{g}}\right)(x)[/tex] =(x+2)/( 4x+3)
Hence, the result of the following: [tex]\left(\frac{\mathrm{h}}{\mathrm{g}}\right)(x)[/tex] is (x+2)/( 4x+3).
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suppose a department store wants to estimate the average age of the customers of its contemporary apparel department, correct to within 2 years, with level of confidence equal to 0.95. management believes that the standard deviation is 8 years. the sample size they should take is .
By using the formula for sample size, it can be calculated that the sample size is 62
What is sample?
At first it is important to know about population.
Population is the group of items from where samples are taken for study and research and for statistical purpose
A subset of population is called sample.
Here, margin of error E = 2
Value of z for 95 % confidence interval = 1.96
Standard deviation = 8
Sample size = [tex](\frac{1.96 \times 8}{2})^2[/tex] [tex]\sim[/tex] 62
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if 17% of men are bald, what is the probability that at most 140 in a random sample of 900 men are bald? use normal to binomial
If 17% of men are bald, then the probability that at most 140 in a random sample of 900 men are bald, is 0.1335.
In the given question, if 17% of men are bald, then we have to find the probability that at most 140 in a random sample of 900 men are bald.
As given that; 17% of men are bald.
So,p=0.17
Let X=Number of men that are bald
Sample size, n=900
Here X follows binomial distribution with parameters n= 900 and p =0.17
Since np≥5 and n(1-p)≥5, We can use normal approximation to the binomial with continuity correction.
So,Binomial can be approximated to normal with;
mean, μ=np
μ = 900*0.17
μ = 153
Standard deviation, σ = √np(1-p)
σ = √900*0.17*(1-0.17)
σ = √153*0.83
σ = √126.99
σ = 11.269
So, X→Normal (μ = 153, σ = 11.269)
Then, X= (X-μ)/σ
X=(X-153)/11.269
We need to find the probability that at most 140 in a random sample of 900 men are bald i.e. we need to find P(X≤140)
P(X≤140) =P(X<140+0.5) [using continuity correction factor]
P(X≤140) =P(X<140.5)
P(X≤140) =P(z<(X-153)/11.269)
P(X≤140) =P(z<(140.5-153)/11.269)
P(X≤140) =P(Z<-1.11) [z score rounded to 2 decimal places]
P(X≤140) =0.1335
Hence, if 17% of men are bald, then the probability that at most 140 in a random sample of 900 men are bald, is 0.1335.
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a computer software developer would like to use the number of downloads (in thousands) for the trial version of his new shareware to predict the amount of revenue (in thousands of dollars) he can make on the full version of the new shareware. attached below is the output from a simple linear regression along with the residual plot and normal probability plot obtained from a data set of 30 different sharewares that he has developed. what is the correct null hypothesis for testing whether there is a linear relationship between revenue and the number of downloads?
We can say that there is sufficient evidence that revenue and the number of downloads are linearly related.
What is the null hypothesis?
The null hypothesis is a common statistical theory that asserts that no statistical relationship or significance exists between two sets of observed data and measured phenomena based on a single observed variable.
Hypothesis:
[tex]H_0:\rho_1=0\\H_1:\rho\neq0[/tex]
Test statistic:
[tex]t=r\times\sqrt{\frac{n-2}{1-r^2} }\\\\ t=(0.8691)\times\sqrt{\frac{30-2}{(1-0.8691)^2} } \\\\t=9.2974[/tex]
D.F. = n - 2 = 28
P-value = P-value at t = 9.2974, ∝=0.05, 28 d.f. is
P-value = 0.000
Conclusion: Since. P-value < ∝=0.05, so we have to reject the null hypothesis.
Hence, we can say that there is sufficient evidence that revenue and the number of downloads are linearly related.
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Please answer! Question is below! Thanks!
Answer:
y=4x+4
Step-by-step explanation:
slope intercept form is y=mx+b
m is slope
B is y intercept
To find slope we use y2-y1/x2-x1
16-(-4)/3-(-2)
20/5
4 is the slope
We can fill this in
y=4x+b
To find b we fill in any coordinates
-4=4(-2)+b
-4=-8+b
+8. +8
4=b
Now we can fill it in
y=4x+4
Hopes this helps please mark brainliest