The following is an excerpt from a paper published in BMJ (formerly the British Medical Journal) in 1994:

Charig et al undertook a historical comparison of success rates in removing kidney stones. Open surgery had a success rate of 78% (273/350) while a minimally invasive procedure called percutaneous nephrolithotomy had a success rate of 83% (289/350), an improvement over the use of open surgery. However, the success rates looked rather different when stone diameter was taken into account. This showed that, for stones of <2 cm, 93% (81/87) of cases of open surgery were successful compared with just 83% (234/270) of cases of percutaneous nephrolithotomy. Likewise, for stones of >/=2 cm, success rates of 73% (192/263) and 69% (55/80) were observed for open surgery and percutaneous nephrolithotomy respectively.

The main reason why the success rate reversed is because the probability of having open surgery or percutaneousnephrolithotomy varied according to the diameter of the stones. In observational (nonrandomized) studiescomparing treatments it is likely that the initial choice of treatment would have been influenced by patients'characteristics such as age or severity of condition; so any difference between treatments could be accounted for bythese original factors. Such a situation may arise when a new treatment is being phased in over time. Randomizedtrials are therefore necessary to demonstrate any treatment effect.

This is an example of Simpson's paradox because:

a. when the lurking variable (size of the stone) is introduced, the conclusions are reversed (percutaneous nephrolithotomy turns out to be less successful at removing them).
b. when the lurking variable (size of the stone) is introduced, the conclusions are reversed (percutaneous nephrolithotomy turns out to be more successful at removing them).
c. when the lurking variable (age or severity of the condition) is introduced, the conclusions are reversed (percutaneous nephrolithotomy turns out to be less successful at removing them).
d. when the lurking variable (age or severity of the condition) is introduced, the conclusions are reversed (percutaneous nephrolithotomy turns out to be more successful at removing them).

Answers

Answer 1

Answer: a. when the lurking variable (size of the stone) is introduced, the conclusions are reversed (percutaneous nephrolithotomy turns out to be less successful at removing them).

Step-by-step explanation: Simpson's Paradox happens when a group of data shows a relationship in each group but it is reversed when the group is combined.

In the BMJ paper, percutaneous nephrolithotomy had a bigger successful rate than open surgery. But, the rates are reversed when the diameter (size) of the stone is included in the research. So, an individual group of data had a relationship and a factor reversed the relationship. This is an example of Simpson's Paradox.

Answer 2

Excerpt form the paper in BMJ.

The excerpt is taken from the paper that got published in the british medical journal of 1994. Ths journal was understand for a historical comparison of the success rates in kidney stone removal. As the success rate of the surgery was about 83%.

Hence the answer is lurking variable is introduced, the conclusions are reversed.

As per the excerpt of the Simpsons paradox the  such as rate of 78% and minimal invasive procedure called the percutaneous has a success rate of 83% thus better over open surgery.Thus the option A is correct. The variable size of stone and conclusion was the opposite.

Learn more about the  undertook a historical.

brainly.com/question/12653054.


Related Questions

Write answer in Simplest Form

Answers

35/36

hope this helps

Charlotte has 30 beads. She has 8 more red beads than blue beads.
Which equation represents this situation?

Answers

Answer:

I think it is the last One

Step-by-step explanation:

Answer:it’s the last one

Step-by-step explanation: I did the test

17.52 - 106
(7.2 + 1.09)

Answers

Answer:

-88.48

8.29

Step-by-step explanation:


2(3x + 3) + 2(4x) = 48
6x + 6 + 8x = 48
14x + 6 = 48
14x = 54
x= 3.86


What’s is the mistake

Answers

Are you asking like In the equation? Like what’s the mistake
x doesn’t equal 3.86 it equals just 3

6. Jessie thinks that the first step in solving the equation shown below is to use the addition
property of equality. His friend Robin thinks that the multiplication property of equality
could be used first. Who is correct and why?
3
5
ixto
A. Jessie is correct because can first be added to both sides of the equation.
B. Robin is correct because both sides of the equation can first be multiplied by 10
C. Both are correct because the first step can be either to add 3/2 or to multiply by 10 on
both sides of the equation.
D. Neither is correct because neither adding nor multiplying by 10 on both sides of the
equation is a valid step.

Answers

The equation is missing and it is;

(2/5)x - 3/2 = (5/2)x + 6

Complete options are;

A. Jessie is correct because 3/2 can first be added to both sides of the equation.

B. Robin is correct because both sides of the equation can first be multiplied by 10

C. Both are correct because the first step can be either to add 3/2 or to multiply by 10 on both sides of the equation.

D. Neither is correct because neither adding nor multiplying by 10 on both sides of the

Answer:

option B: Robin is correct because both sides of the equation can first be multiplied by 10

Step-by-step explanation:

The given equation is;

(2/5)x - 3/2 = (5/2)x + 6

Now, looking at this, we have fraction terms. Thus, the first step will be to find a way to clear the denominators in order to make every term a whole number.

The denominators we have are: 2 and 5.

So to clear the denominator we'll multiply each term by 10 which is a product of 2 and 5.

Looking at the options, the correct answer is option B: Robin is correct because both sides of the equation can first be multiplied by 10

What’s the answer to this problem 3x36-(81/9-8)+16/4=

Answers

Answer:

108x - 69

Step-by-step explanation:

Reduce the numbers with greatest common divisor 9 Calculate the productReduce the fraction with 4Subtract the numbersCalculate the sum

What is 2(a +8) pls help me I want to pass

Answers

the answer could possibly be

2(a+8)
2xa=2a
2x8=16

Answer=
2a+16

Answer:

2a+16

Step-by-step explanation:

Your first distribute 2(a+8) and get 2a+16.

Whenever a number is in front of a group of numbers in parenthesis, then it  is always multiplying. You have to multiply both numbers, and that's how I got 2a+16. Hopefully this helps!

Simplify this complex fraction 2/5 divided by 5/8

Answers

Answer:

1 19/21

Step-by-step explanation:

brainliest pls :D

Answer:

0.64

Step-by-step explanation:

Let's think about a few simple examples. Once you understand them, you

will be able to put them together to make harder problems.

Ex: What is 2 divided by 1/5? Here are 2 blocks:

    +---------+---------+

    |         |         |

    |         |         |

    |         |         |

    |         |         |

    |         |         |

    |         |         |

    |         |         |

    |         |         |

    |         |         |

    +---------+---------+

Here is 1/5 of a block (the shaded part):

    +---------+

    |XXXXXXXXX|

    +.........+

    |         |

    +.........+

    |         |

    +.........+

    |         |

    +.........+

    |         |

    +---------+

To divide 2 by 1/5, we divide 2 blocks into pieces the size of the 1/5

block.

    +---------+---------+

    |         |         |

    +.........+.........+

    |         |         |

    +.........+.........+

    |         |         |

    +.........+.........+

    |         |         |

    +.........+.........+

    |         |         |

    +---------+---------+

There are 10 pieces this size in the 2 blocks. In other words,

    2 divided by 1/5 = 10

That's the same as

    2 x 5 = 10

Do you see why? To make 1/5 size blocks, we had to make each whole

block into 5 pieces. In other words, we multiplied the number of

pieces by 5.

Next problem:

   2 divided by 2/5 = ?

Here is 2/5 of a block (the shaded part):

    +---------+

    |XXXXXXXXX|

    +.........+

    |XXXXXXXXX|

    +.........+

    |         |

    +.........+

    |         |

    +.........+

    |         |

    +---------+

Let's divide the 2 blocks into pieces this size.

    +---------+---------+

    |         |         |

    +         +         +

    |         |         |

    +.........+.........+

    |         |         |

    +         +         +

    |         |         |

    +.........+.........+

    |                   |

    +---------+---------+

The bottom block is a different shape, but it's the same size, because

it's made of 2 1/5-size pieces. Since the pieces we want are twice as

big, there are only 1/2 as many of them. The answer is

    2 divided by 2/5 = 10/2 = 5

This is the same as

    2 x 5/2 = 5

Do you see how the two equations are related? You take the fraction,

2/5, and "turn it upside down" (in math words, we say "invert the

fraction," or "take its reciprocal"). Then replace the division sign

by a multiplication sign.

Now we can tackle harder problems. The same method always works, even

if the answer isn't a whole number as in the simple examples. For

instance,

    5 divided by 3/8 = ?

Ex: Invert the fraction 3/8; you get 8/3. Then multiply by this fraction:

    5 x 8/3 = 40/3 = 13 1/3

We can even replace the whole number in the problem with a fraction,

like this:

    5/7 divided by 3/8 = ?

    5/7 x 8/3 = ?

     5     8     40       19

    --- x --- = ---- = 1 ----

     7     3     21       21

If you are comfortable with multiplying fractions, then you will have

no trouble dividing fractions. Just remember: invert the fraction you

are dividing by (the divisor), and multiply instead of dividing. Hope this helps! :)

Find the area of the polygon with the given vertices.
G(2,2) H(3,-1) J(-2,-1)

Answers

Answer:

8

Step-by-step explanation:

hope this helps you

2(67+8)*3 plz help
A. 450
B.908
C.154
D 679

Answers

Answer:

A. 450

Step-by-step explanation:

Answer:

its a the answer 450

Step-by-step explanation:

Here is why

2(67+8) (3)

= (2) (75) (3)

=(150) (3)

= 450

hope it helps

The equations are in the picture

Answers

Answer:

m∠R = 56°

Step-by-step explanation:

2(8x - 12) = 16x - 24

2(3x + 5) = 6x + 10

16x + 6x + 10 - 24 = 360

22x - 14 = 360

22x = 374

x = 17

3x + 5 = 17 x 3 = 51 + 5 = 56

please answer this equation fast !!!

Answers

Answer:

Question 1

C) 00:00

Question 2

B) 37.68 cm

hope this helps!

I Need Help In Solving For X

Answers

23x - 5 = 21x + 5

2x = 10

x = 5

The value of x is 5.

How many feet tall is it

Answers

I believe 12 inches because 1 ft is equal to 12 inches.

19+22+11 route written correctly using the commutative property and then simplify correctly

Answers

Answer:

11 + 22 + 19 = 52

Step-by-step explanation:

You can simplify 52 into 13, here's why ↓

4 x 13 = 52

Hope this helps!If so, give thanks! Keep learning and stay cool.

Which two statements true ?

Answers

1 & 3 I thinkkkkkkk

Henry painted a picture of his house on canvas. The actual width of the driveway is 20 fr. If it represented with a. width of 4in on the canvas, what was the scale factor used?

Answers

5 feet=1 inch 20 / 4=5 so 5 feet = 1 inch

Given that one of the angles in a triangle is 60°, select the correct option for each statement.

Answers

(i) might be true, you can have a scalene triangle with one angle being 60°, (if all the other angles were also 60°) BUT we don’t know the other angles so it is possible that it is not a scalene as well

(ii) must be true, because all angles in a triangle must add up to 180° (120°+60°=180°)

(iii) cannot be true, because in order to be obtuse that means the other angles must both be bigger than 90°, and 91°+ 91° is 182°,but ALL three angles of a triangle must equal 180° together therefore there wouldn’t be any room for the 60°

(iiii) Might be true, 60° plus a right angle (90°) gives you 150°, and the other angle would be 30°, so you can’t tell for sure if it’s a right angle triangle but it is possible that is could be.

does p-4=-9+p have no solution, one solution, or infinite solutions

Answers

the equation has no solutions

We discovered that 650 GSS respondents in 2006 watched television for an average of 2.98 hrs/day, with a standard deviation of 2.4 hours. Answer the following questions, assuming the distribution of the number of television hours is normal. What is the Z score for a person who watches more than 8 hrs/day. 2.09 What proportion of people watch 5 hrs/day or more television? 0.84 How many does this correspond to in the sample? 130 What number of television hours per day corresponds to a Z +1. -0.825 What is the percentage of people who watch between 1 and 6 hours of television per day? Please round to a whole number 1.26

Answers

Answer:

a)2.09

b) 0.2

c) 130 correspondents

d) 5.38 hours per day

e) 69%

Step-by-step explanation:

The formula for calculating a z-score is is z = (x-μ)/σ,

where

x is the raw score,

μ is the population mean,

σ is the population standard deviation.

Mean = average of 2.98 hrs/day, Standard deviation = 2.4 hours.

a) What is the Z score for a person who watches more than 8 hrs/day.

z = (x-μ)/σ

= 8 - 2.98/2.4

= 2.09167

≈ 2.09

b) What proportion of people watch 5 hrs/day or more television?

z = (x-μ)/σ

= 5 - 2.98/2.4

= 0.84167

P-value from Z-Table:

P(x<5) = 0.80001

The proportion that watches 5 hrs/day or more television?

P(x>5) = 1 - P(x<5) = 0.19999

≈ 0.2

c) How many does this correspond to in the sample?

From the question we are told:

650 GSS respondents in 2006 watched television for an average of 2.98 hrs/day, with a standard deviation of 2.4 hours.

Hence, the proportion that corresponds to people who watch 5 hrs/day or more television form the samples is

0.2 × 650

= 130 correspondents.

d) What number of television hours per day corresponds to a Z +1.

z = (x-μ)/σ

+1 = x - 2.98/2.4

Cross Multiply

1 × 2.4 = x - 2.98

2.4 = x - 2.98

x = 2.4 + 2.98

x = 5.38 hours per day

e) What is the percentage of people who watch between 1 and 6 hours of television per day?

Step 1

For 1 hour

z = (x-μ)/σ

= 1 - 2.98/2.4

= -0.825

Probability value from Z-Table:

P(x = 1) = 0.20469

Step 2

For 6 hours

z = (x-μ)/σ

= 6 - 2.98/2.4

= 1.25833

Probability value from Z-Table:

P(x = 6) = 0.89586

The percentage of people who watch between 1 and 6 hours of television per day is

P(x = 6) - P(x = 1)

= 0.89586 - 0.20469

= 0.69117

Converting to percentage =

0.69117 × 100

= 69.117 %

Approximately = 69%

food is tight and you are given 98 oz. of bread every week. If you want to eat the same amount of bread every day, how many oz. should you eat each day?​

Answers

19.6 is the answer i believe

Answer:

14 oz

Step-by-step explanation:

A week has 7 days and you need to ration your bread over them.

98 / 7 = 14


If (x+ 4) is a factor of polynomial p, which statement must be true?
A. P(-4) = 0
B. p(4) < 0
C. p(4) = 0
D. P(-4) > 0

Answers

Answer:

A

Step-by-step explanation:

X+33% of X = 266
Answer:- 200

Answers

x + (1 + 33%) = 266

x * 1,33 = 266

x = 266 : 1,33

x = 200

Hello

x + 0.33 x =  266

1.33 x = 266

x =  - 200

20 POINTS
Part D How many of the 320 million Americans would you predict wear CORRECTIVE lenses?

Answers

Answer:

320,000,000 * 0.638 = 204,160,000

Step-by-step explanation:

Assuming the sample is a good representation of the people from the United States.

Since there were 1,000 surveyed... and 638 of them were wearing glasses, that makes a proportion of 638 out of 1,000 people, or 63,8 / 100 people... so 63.8%... or 0.638

So, if we assume that the US population is of 320 million, how many people does that make wearing glasses.... we just have to multiply 320M by 0.638

Prove that 5^7 + 5^6 is divisible by 6

5^7 + 5^6 = __ • 6

Answers

Answer:

Step-by-step explanation:

[tex]5^{7}[/tex] + [tex]5^{6}[/tex] = 5 × [tex]5^{6}[/tex] + [tex]5^{6}[/tex] = [tex]5^{6}[/tex] ( 5 + 1 ) = [tex]5^{6}[/tex] · 6

Hey there!

[tex] -› \: {5}^{7} + {5}^{6} [/tex]

[tex]-› 78,125 + 15,625[/tex]

[tex]-› \: 93750[/tex]

[tex]-› \: 93750 \div 6[/tex]

[tex]-› \: 15625[/tex]

Therefore, It's divisible by 6

what is 12x12-11+14-18=?

Answers

Answer:

129

Step-by-step explanation:


First we check for parentheses which there is none.

We would first do 12 x 12=144

Then we would do addition and subtraction left to right.

so just in order.

Second we would do 144 - 11=133


Third we would do 133 + 14=147


And last 147 - 18=129 And there's your answer.

Hope it helps have a great day:)

is my answer correct or no bc im struggling with this question ​

Answers

Answer:

Yes, you got it correct, good job.

Trey made a scale drawling of a micro chip using a scale of 2 inches long and 4inches wide

Answers

Answer:

Perimeter- 12 inches

Area- 8 inches

Shape- Rectangle

(I didn't know what the question was)

Assume the random variable X has a binomial distribution with the given probability of obtaining a success. Find the following probability, given the number of trials and the probability of obtaining a success. Round your answer to four decimal places.

P(X≥18), n=20, p=0.9

Answers

the answer to this is 20.9

Assuming that 6 in 10 automobile accidents are due mainly to a speed violation, find the probability that among 8 automobile accidents, 6 will be due mainly to a speed violation (a) by using the formula for the binomial distribution; (b) by using Table A.1.

Answers

Answer:

A ) 0.2090 B) .2090

Step-by-step explanation:

∙Let random variable XX represent the number of accidents due to speed violation among 8 automobile accidents.

Lets consider it success if an accident is due to speed violation.

-Probability of a success in each trial is p = 6/10 = 0.6

-Because the trials are independent, XX has a binomial distribution with parameters n = 8n=8 and p = 0.60p=0.60

The probability that among 8 automobile accidents, 6 will be due mainly to a speed violation will be 0.75.

What is probability?

It is defined as the ratio of the number of favorable outcomes to the total number of outcomes, in other words, the probability is the number that shows the happening of the event.

 

It is given that, the probability that among 8 automobile accidents, 6 will be due mainly to a speed violation.

In everyday life, risk modeling and assessment involve the use of probability theory. Actuarial science is used by the insurance sector and markets to set pricing and decide which securities to trade. Environmental regulation, entitlement analysis, and financial regulation are all areas where governments use probabilistic methods.

Probability =favorable outcome/ total outcome

Probability = 6/8

Probability =0.75

Thus, the probability that among 8 automobile accidents, 6 will be due mainly to a speed violation will be 0.75.

Learn more about the probability here:

brainly.com/question/11234923

#SPJ2

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