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chubhunter [2.5K]
3 years ago
11

A important study in the history of case-control methods was completed in 1950 by Doll & Hill. This study found that 647 of

the 649 lung cancer cases were smokers. In contrast, 622 of 649 controls smoked.
Mathematics
1 answer:
Sladkaya [172]3 years ago
3 0

Answer:

Evidence of an increased risk of lung cancer associated with cigarette smoking was sought by Doll and Hill. In one study, 649 lung cancer cases were matched by age, and gender to 649 controls; 647 of the cases and 622 of the control had a history of smoking cigarettes.a.Name the type of study. Case control studyb.Create the appropriate 2X2 table for the study. (2 points)Lung CancerControlsSmokers647622Nonsmokers227Total649649c.Calculate the appropriate measure of association for the study. (4 points)The odds ratio: Cases = 647 / 2 = 323.5The odds ratio: Control = 622 / 27 = 23.03The odds ratio = 23.03 / 323.5 = 14.04 d.Interpret the results. (2 points)Smokers are 14 times more likely to develop lung cancer than non-smokers.

Step-by-step explanation:

You might be interested in
An independent random sample is selected from an approximately normal population with an unknown standard deviation. Find the p-
Vedmedyk [2.9K]

The complete question is missing, so i have attached it

Answer:

A) Reject the null hypothesis

B) Reject the null hypothesis

C) Fail to reject the null hypothesis

D) Reject the null hypothesis

Step-by-step explanation:

A) We are given;

Ha: μ > μ_o (This is thus, a one-tail problem)

n = 11

T = 1.91

Using online p-value from t-score calculator as attached with a DF = n - 1 = 11 - 1 = 10, and t-value = 1.91, and significance level of 0.05, and 1 tail, we have;

The p-value is 0.042602

P-value is less than significance level, thus, we will reject the null hypothesis

B) We are given;

Ha: μ < μ_o (This is thus, a one-tail problem)

n = 17

T = -3.45

Using online p-value from t-score calculator as attached with a DF = n - 1 = 17 - 1 = 16, and t-value = 1.91, and significance level of 0.05, and 1 tail, we have;

The p-value is  0.001647

P-value is less than significance level, thus, we will reject the null hypothesis

C)We are given;

Ha: μ ≠ μ_o (This is thus, a two-tail problem)

n = 7

T = 0.83

Using online p-value from t-score calculator as attached with a DF = n - 1 = 7 - 1 = 6, and t-value = 0.83, and significance level of 0.05, and 2 tail, we have;

The p-value is 0.438308.

P-value is higher than the significance level, thus, we will fail to reject the null hypothesis.

D) We are given;

Ha: μ > μ_o (This is thus, a one-tail problem)

n = 28

T = 2.13

Using online p-value from t-score calculator as attached with a DF = n - 1 = 28 - 1 = 27, and t-value = 2.13, and significance level of 0.05, and 1 tail, we have;

The p-value is 0.021218

P-value is lower than the significance level, thus, we will reject the null hypothesis

P-value is lower than the significance level, thus, we will reject the null hypothesis.

6 0
3 years ago
The sum of 5 consecutive integers is 110, what is the fourth number in this sequence?
Xelga [282]

The answer is:  " 23 " .

    →  The fourth number in the sequence is:  " 23 " .

_____________________________________

Explanation:

To solve:

 " x + (x + 1) + (x + 2) + (x + 3)  + (x + 4) = 110 " ;

in which:

 "x" = The first number in these sequence;

 "(x + 1 )" = the second number in the sequence;

 "(x + 2)" = the third number in the sequence;

 "(x + 3)" = the fourth number in the sequence;

 "(x + 4)" = the fifth number in the sequence;

_____________________________________

Solve for the "fourth number in the sequence" ; or:  "(x + 3)" ;

_____________________________________

Given:  " x + (x + 1) + (x + 2) + (x + 3) + (x + 4) = 110 " ;

                     ↔   " x + x + 1 + x + 2 + x + 3 + x + 4 = 110 " ;

→  Solve for "x" ;  

→  then,  solve for "(x + 3)" ;  

     →  which is the fourth number in this sequence;

_____________________________________

→  " x + x + 1 + x + 2 + x + 3 + x + 4= 110 " ;

      "5x + 1 + 2 + 3 + 4= 110 " ;

      " 5x + 10 =  110 " ;

Solve for "x" :

     Subtract "10" from EACH SIDE of the equation; as follows:

      " 5x + 10 - 10 =  110 - 10 " ;

 to get :

      "  5x = 100 " ;

Now, divide EACH SIDE of the equation by "5" ;

to isolate "x" on one side of the equation; & to solve for "x" ;  as follows:

         5x / 5  = 100 / 5 ;

to get:

         "  x  = 20 "  .

_____________________________________

Now, to find the fourth number in the sequence:

 →  " (x + 3) " ;

→  Substitute "20" for "x" ;

    " x + 3 = 20 + 3 = 23" ;

_____________________________________

The answer is:  " 23 " .

The fourth number in the sequence is:  " 23 " .

_____________________________________

Let us check our work:

If there are five "5" numbers in the sequence, and "23" is the "fourth number" , then:  "24" is the "fifth number" .

As such:  "22" is the "third number" ;  "21" is the "second number" ; and "20" is the "first number" .  Is this consistent with:  "x = 20" as the "first number" ?  Yes!

Thus,  "20 + 21 + 22 + 23 + 25 = ?  110 ?  ? ;

→  20 + 21 = 41 ;

→  41 + 22 = 63 ;

→  63 + 23 = 86 ;

→  86 + 24 = 110 .    Yes!

_____________________________________

Hope this answer is helpful!

Best wishes in your academic pursuits—

 and within the "Brainly" community!

_____________________________________

5 0
3 years ago
3. The three salespeople for a local advertising firm are Lola, Ahmed, and Tommy. Lola sold $2030 in ads, Ahmed sold $1540, and
Salsk061 [2.6K]
3. (a)

Add the three totals.

Total sales for all three: $2030 + $1540 + $1800 = $5370

Now divide each person's sales by the total sales to find each person's fraction of the sales.

Lola: 2030/5370
Ahmed: 1540/5370
Tommy: 1800/5370

3. (b)

Multiply each fraction from part (a) by $100.

Lola: 2030/5370 * $100 = $37.80
Ahmed: 1540/5370 = $28.67
Tommy: 1800/5370 = $33.52



6 0
3 years ago
Find the measure of ZDCF. C F mDF = 49 G E MEG = 127 Find the measure of angle DCF​
AleksandrR [38]

Answer:

Step-by-step explanation:

Comment

If two secants intersect outside a circle (as these two do) then the angle at which they meet is 1/2 the difference between the intersected arcs. Put much simpler <DCF = 1/2 (arc EG - arc DF)

Givens

Arc EG = 127

Arc DF = 49

Solution

<DCF = 1/2(127 - 49)

<DCF = 1/2(78)

<DCF = 39

8 0
2 years ago
Find the exact circumference of a circle with diameter equal to 8 ft. 8 ft. 16 ft. 64 ft.
maria [59]

ANSWER

8π ft

EXPLANATION

The circumference of a circle is calculated using the formula C=πd.

Where d=8 is the diameter of the circle.

We substitute d=8 into the formula to obtain,

C=8π ft.

Because we are looking for the exact circumference, we leave the answer in terms of π.

6 0
3 years ago
Read 2 more answers
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