a large study in the uk was done to determine if there was a link between cell phone usage and brain cancer. the study set out to determine if using a cell phone more, increased the likelihood of getting brain cancer. the study took about 800,000 women and asked them to report their cell phone use in 1999, 2005, and again in 2009. in 2009, they recorded the proportion of women who had developed brain cancer. their conclusion was "in this large prospective study, mobile phone use was not associated with increased incidence of glioma, meningioma or non-cns cancers." is this an observational study or an experiment? justify your answer.

To find the margin of error we have to use the formula,

Margin of error =  Z * ơ / √n ,

Where

z = critical factor

ơ = population standard deviation

n = sample size

Now we have to find confidence interval

Confidence interval can be defined as a range of values so defined that there is a specified probability that the value of a parameter lies within it.

The confidence interval of a statistical data can be written as.

x+/-zr/√n

x+/-ME

Where margin of error ME = zr/√n

Given that;

Mean = ц

Standard deviation r = 25

Number of samples n = 41

Confidence interval = 95%

z(at 95% confidence) = 1.96

Xbar = 60.............(1)

Xbar + E = 66.........(2)

from equating both the equations we get

E= 6

and for finding the value of margin of error we know that its the half of the E

Margin of error = E/2

=6/2

=3

Therefore , the Margin of error is 3

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The monthly payment amount a woman has to pay for the car is $462.91.

Here we have to find the monthly payment amount.

The cost of car = $23,800

Down payment = $3,500

Rate(r) = 4.5%

time(t) = 4 years

Periodic interest(i) = 0.045/12

Formula to calculate monthly payment:

A = P i( 1 + i[tex])^{n}[/tex] / ( 1 + i[tex])^{n}[/tex] - 1

Loan amount = 23800 - 3500

                      = $ 20300

A = 20300 ( 0.045 /12 ( 1 + 0.045/12[tex])^{48}[/tex])/ (1 + 0.045/12[tex])^{48}[/tex] - 1

  = 20300× 0.004488 / 0.196814

  = 462.91

Therefore the monthly payment is $462.91.

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Answer: 5^2

Step-by-step explanation:

5 x 5 = 25

and (x-7)^2 = 25

The converse of the following conditional True which is If a polygon is a triangle, then it has exactly three sides."

In terms of geometry, a triangle is a three-sided polygon with three edges and three vertices. The triangle's interior angles add up to 180°.

A polygon has precisely three sides if it is a triangle. The opposite is also accurate.

Contrarily, a polygon is a triangle if it has precisely three sides. Both of the statements can be joined to create a biconditional because they are both true.

Thus, the converse of the following conditional True which is If a polygon is a triangle, then it has exactly three sides."

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Answer:

Step-by-step explanation: x is the number of days she is booked.

List an equation

748+86x=734+87x

x=14

14 nights and plugging x into the equation 1952 points

If one tries to store a list of single-digit numbers in his or her short-term memory, then he will be able to store 7 numbers on average.

What is short-term memory?

Short-term memory is a concept in psychology that defines the capacity for holding a small amount of information in mind for a short interval. The concept of short-term memory is given by Atkinson-Shiffrin. The information of short-term memory can be transformed into long-term memory through rehearsal.

According to several studies, short-term memory has a space limit of 7 ± 2 chunks of information. The fact is written by a cognitive psychologist of Harvard University named George A. Miller and was published in 1956 in psychological reviews.

Hence, If one tries to store a list of single-digit numbers in his or her short-term memory, then he will be able to store 7 numbers on average.

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Step-by-step explanation:

[tex] {3}^{10 - 6} [/tex]

[tex] = {3}^{4} [/tex]

After using the test statistic z, P(3.6<X<53.5) = 0.967.

In the given question, suppose X is a normal random variable with mean 35 and sdev 10.

We have to find P(3.6<X<53.5).

Fro the given question,

Mean x = 35

sdev s = 10

Z = X - mu / sd

P(3.6<X<53.5) = P ( 3.6-35/10 < Z < 53.5-35/10 )

P(3.6<X<53.5) = P ( -31.4/10 < Z < 18.5/10 )

P(3.6<X<53.5) = P ( -3.14 < Z < 1.85 )

P(3.6<X<53.5) = P ( Z < 1.85) - P ( Z < -3.14)

left tail of both

P(3.6<X<53.5) = 0.9678 - 0.0008

P(3.6<X<53.5) = 0.967

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The right answer is:

Suppose X is a normal random variable with mean 35 and sdev 10. Find P(3.6<X<53.5)

The margin of error for a sampling distribution is found as 3.34.

Margin of error = z × σ/√n

Thus, put the values;

z-score for 93% confidence level = 1.67

Margin of error = 1.67 ×12/√36

Margin of error = 3.34

Thus, the margin of error for a sampling distribution is found as 3.34.

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It will take 7 hours to paint a room when Sonia and Roman works together.

Given,

Time taken by  Sonia to paint a room = 12 hours

Time taken by Roma to paint the same room = 15 hours

We have to find the time taken by both of them to paint the room if they work together.

Here,

Sonia takes 12 hours

Roman takes 15 hours

LCM of 12 and 15 = 60

12 × 5 = 60

15 × 4 = 60

Total number of works is 60

Now,

Number of works done by Sonia = 5 in an hour

Number of works done by Roman = 4 in an hour

So,

5 + 4 = 9 work can be done by them together in an hour

Then,

Time taken to complete 60 works;

60/9 = 6.66 ≈ 7 hours

That is,

In 7 hours Sonia and Roman paint a room together.

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Assuming the population standard deviation is known and the standard deviation of the sample mean x : option (b) is correct : the standard error of the sample mean decreases.

In probability theory, the central limit theorem (CLT) states that the distribution of a sample variable approximates a normal distribution (i.e., a “bell curve”) as the sample size becomes larger, assuming that all samples are identical in size, and regardless of the population's actual distribution shape.

Standard deviation is a calculation of the dispersion or variation in a set of numbers. If the standard deviation is a small number, it means the data points are close to their average value. If the deviation is large, it means the numbers are spread out, further from the mean or average.

There are different ways to write out the steps of the population standard deviation calculation into an equation. A common equation is:

                          σ = ([Σ(x - u)2]/N)1/2

Where:

σ is the population standard deviation

Σ represents the sum or total from 1 to N

x is an individual value

u is the average of the population

N is the total number of the population

A sample mean is an average of a set of data . The sample mean can be used to calculate the central tendency, standard deviation and the variance of a data set. The sample mean can be applied to a variety of uses, including calculating population averages.

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4.84 HP is the amount of work energy used.

Given info,

A helicopter is lifting an 800-pound unit at a rate of 200 feet per minute.

1 horsepower = 550 foot-pounds per second

⇒ 800 x 200 = 160,000 foot-pounds per minute

                      = 160,000/60 foot pounds per second.

Horsepower = 160,000/60 * 550 = 428/33

                                                       = 4.848 HP

Therefore, the horsepower of work energy used is 4.84 HP

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The volume of foam needed for the 45 cones is

v = 16,956 cm³

We know that the volume of a cone of diameter F and height H is:

V = pi*(D/2)²*H/3

Where pi = 3.14

Here we know that:

D = 12cm

H = 10cm

And we want to find the volume of 45 of these cones, so the total volume of foam needed is:

v = 45*V = 45*(3.14*(12cm/2)²*10cm/3

v = 16,956 cm³

That is the volume of foam needed.

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Answer:

it's 20 if u look closely

7m-(7n-18m) is an expression which is equivalent to (2mn)^4/6m^-3 n^-2 Assume m=0 n=0​

What is a expression in maths?

An expression in math is a sentence with a minimum of two numbers or variables and at least one math operation. This math operation can be addition, subtraction, multiplication, or division. The structure of an expression is: Expression is (Number/variable, Math Operator, Number/variable)

for example 4m +5 where 4 is the coefficient of m and 5 is the constant term in other word 4m and 5 are the term of the expression and m is the variable in the expression and addition is the operator.

m=0, n=0.

8m^7n^6/3 10m^7n^6/3 8m^16n^12/3 m^4n^6/3

-7m-(3n-(8m-4n-10m)

-7m-(3n-(8m-4n+10m))

-7m-(3n-(18m-4n))

-7m-(3n-18m+4n)

-7m-(7n-18m)

complete question is

Which expression is equivalent to (2mn)^4/6m^-3 n^-2? Assume m=0 n=0​

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A statement which is true about the graphs of f(x) = x and g(x) = f(x + 7) is: C. g(x) is the graph of f(x) translated 7 units to the left.

In Mathematics, the translation a geometric figure or graph to the left simply means subtracting a digit from the value on the x-coordinate of the pre-image while the translation a geometric figure or graph downward simply means subtracting a digit from the value on the y-coordinate (y-axis) of the pre-image.

In Geometry, g(x + 7) or g(x) = f(x + 7) simply means shifting a graph 7 units to the left as illustrated by the graph shown in the image attached below.

In this context, we can reasonably infer and logically deduce that the parent function f(x) = x was shifted by 7 units to the left.

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Complete Question:

Which of the following statements is true about the graphs of f(x)=x and g(x)=f(x+7)?

A. g(x) is the graph of f(x) translated 7 units down.

B g(x) and f(x) have the same y-intercept.

C g(x) is the graph of f(x) translated 7 units to the left.

D g(x) is the graph of f(x) translated 7 units to the right.

The equation representing the number of bottle Barbara need to sell to earn $100 is; 1.49x + 1.25y = 100.

For the given question-

Let the number of iced tea bottle be 'x'.

Let the number of water bottle be 'y'.

Total price = 100

Thus, the equation for the total cost becomes-

1.49x + 1.25y = 100.

Therefore, the equation representing the number of bottle Barbara need to sell to earn $100 is; 1.49x + 1.25y = 100.

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The square in RMSE is utilized because it consistently provides a positive number for error, preventing errors from canceling one another out, and grants higher weight to values further from the target function, emphasizing locations for which the estimator is unreliable. To reverse the results of squaring, use the square root. 

What is RMSE?

The difference between values (sample or population values) predicted by a model or estimator and the values observed is typically measured using the root-mean-square deviation (RMSD) or root-mean-square error (RMSE).

The RMSD is the quadratic mean of the square root of the second sample moment of the discrepancies between expected values and observed values.

When computations are made outside of the data sample that was used for estimation, the deviations are referred to as errors (or prediction errors) instead of residuals.

The RMSD is used to combine the sizes of predictions' mistakes for different data points into a single indicator of predictive power. .

RMSD is a metric for accuracy that is used to compare the predicting mistakes of various models.

Hence, The square in RMSE is utilized because it consistently provides a positive number for error, preventing errors from canceling one another out, and grants higher weight to values further from the target function, emphasizing locations for which the estimator is unreliable. To reverse the results of squaring, use the square root. 

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a regression equation for this formula, where x represents the number of years enrolled and y represents the tuition.

y = 34000 - 2300x

Regression is a statistical technique that connects one or more independent (explanatory) variables to a dependent variable. If there is a relationship between changes in one or more of the explanatory factors and changes in the dependent variable, it can be shown using a regression model.

The regression equation for this formula would be:

Y = 34,000 - 2,300x

where Y is the tuition cost and x is the number of years in school.

The equation states that the tuition cost for any year in school (x) is equal to the freshman year tuition cost (34,000) minus 2,300 multiplied by the number of years in school (x).For example, if x = 4 (4 years in school), then the tuition cost for that year would be 34,000 - 2,300(4) = 25,400.

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The wire should be anchored to the ground to minimize the amount of wire needed 20 ft from the left pole.

What is the quadratic equation?

ax2 + bx + c = 0 is a quadratic equation, which is a second-order polynomial equation in a single variable. a 0. It has at least one solution because it is a second-order polynomial equation, which is guaranteed by the algebraic fundamental theorem. The answer could be simple or complicated.

Let x (ft) be the distance from the base of the left pole to the anchor point. Since 2 poles has a distance of 30 ft, the distance from the anchor point to the right pole is 30 - x.

The wire length from the top of the left pole to the anchor point is

[tex]L^{2} _{l} = 20^{2} + x^{2} = x^{2} + 400[/tex]

Similarly for the 2nd part of the wire

[tex]L^{2} _{t} = 10^{2} + (30 - x^{2})[/tex]

= 100 + 900 - 60x + x²

= x²+ 1000 - 60x

We want to minimize the length of the wires, or [tex]L^{2} _{l} + L^{2} _{r}[/tex]

[tex]\frac{x}{\sqrt{{x}^2 + 400} } + \frac{x - 30}{\sqrt{{x}^2 + 400}} = 0[/tex]

we can take the first derivative of this and set it to 0

x = 20

Hence, the wire should be anchored to the ground to minimize the amount of wire needed  20ft.

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After solving, the value of Test statistic z is 1.449.

In the given question,

A sample of 1700 computer chips revealed that 36% of the chips fail in the first 1000 hours of their use.

The company's promotional literature states that 39% of the chips fail in the first 1000 hours of their use.

Then we have to find the value of z statistic.

Hypothesized proportion (p) = 36%=0.36

Sample proportion (p') = 39% = 0.39

Sample size (n) = 1700

Hence,

Test statistic z

z= (0.76-0.78)/√(0.78* 0.22/900)

z= (-0.02)/√(0.78* 0.000244)

z= -0.02/√0.00019032

z= -0.02/0.0138

z = -1.449

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There is no error made in claiming that the mean temperature inside the truck is 32 degrees which is 2 degrees more than the required one.

Given, an ice cream truck aims to keep 30 degrees as the mean temperature inside its delivery truck.

one employee claims that the mean temperature inside its delivery truck is more than 30 degrees. the employee conducts a hypothesis test and rejects the null hypothesis.

The mean temperature inside its delivery truck is 32 degrees.

As, the temperature inside the delivery truck should be 30 degrees and should not be greater than 30 degrees then, there is no error made in claiming that the mean temperature inside the truck is 32 degrees which is 2 degrees more than the required one.

So, there is no error made in claiming that the mean temperature inside the truck is 32 degrees which is 2 degrees more than the required one.

Hence, there is no error made in claiming that the mean temperature inside the truck is 32 degrees which is 2 degrees more than the required one.

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Answer:

4/3

Step-by-step explanation:

slope = (y_2 - y_1)/(x_2 - x_1)

slope = (-3 - 1)/(-2 - 1)

slope = -4/(-3)

slope = 4/3

Answer:

2.5a - 1.5 b or

5/2a - 3/2b

Step-by-step explanation:

a + (a - b) + 0.5(a - b) =

a + a - b + 0.5a - 0.5b =

2a - b + 0.5a - 0.5b =

2a - 1.5 b + 0.5a  =

2.5a - 1.5 b

Answer:

1

Step-by-step explanation:

The equation to represent this would be (1 - (1 / 3)) / 2

1 - (1 / 3) = 2 / 3

2 / 3 / 2 = 1 / 3

Unlike fraction 1/7 is converted to equivalent  like fraction 2/14 and the sum of 2/14 + 3/14 = 5/14.

As given in the question,

Given fraction is equal to:

1/7=? + 3/14=?

Here there are two fractions

1/7 and 3/14

LCD( least common denominator) of 7 and 14 is equal to 14.

Now make them like fractions

1/7 is equivalent to

( 1/7) × ( 2/2) = 2/ 14

Now 2/14 and 3/14 are like fractions

Sum of like fractions is:

2/14 + 3/14

= ( 2+ 3) / 14

= 5/ 14

Therefore, the conversion of unlike fraction 1/7 to like fraction is 2/14. And sum of 2/14 + 3/14 = 5/14.

The complete question is:

Convert these unlike fractions to equivalent like fractions and add them. You must use the LCD to get the answer correct. If possible, reduce the final sum. 1/7=? + 3/14=?

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The slope of the straight line is 4/5

The slope of a line is a measure of the ratio between the rise and run of that line. The slope of a line is an integral quantity used to calculate the equation of a line

In general, to find the slope of a line, we need to have the values of any two different coordinates on the line.

The slope of a line basically the change in y-coordinate with respect to change in x-coordinate.

This is easily done with a formula given as

m = y₂ - y₁ / x₂ - x₁

Taking data points from the graph attached;

Substituting the values into the slope equation;

m = -2 - 2 / 0 - 5

m = -4 / - 5

m = 4/5

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