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Oxana [17]
3 years ago
15

Ajar contains "x" black and "y" white balls. What is the probability that a random draw is black?

Mathematics
2 answers:
Levart [38]3 years ago
8 0

Answer:

Step-by-step explanation:

favorable events=x

total number of events=x+y

P=(favorable events)/(total number of events)=x/(x+y)

lubasha [3.4K]3 years ago
6 0
If there are ‘x’ black balls and ‘y’ white balls, then the total number in the jar must be x + y.
Therefore, the probability of picking a black ball is the amount of black balls there are divided by the total, which is x/(x+y)

I hope this helps!
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Day care centers expose children to a wider variety of germs than the children would be exposed to if they stayed at home more o
Ostrovityanka [42]

Answer:

a) The study is an observational study

b) The proportion of children with significant social activity in children with acute lymphoblastic leukemia is approximately 0.802

The proportion of children with significant social activity in children without acute lymphoblastic leukemia is approximately 0.8565

c) The odds ratio is approximately 0.6780

d) The 95% CI is approximately 0.523 < OR < 0.833

e) i) Yes

ii) Children with more social activity have a higher occurrence of acute lymphoblastic leukemia

Step-by-step explanation:

a) An experimental study is a study in which the researcher adds inputs to the study and then monitors the outcomes

An observational study is one in which the researcher observes risk factors and does not intervene in the process

Therefore, the study is an observational study

b) The proportion of children with significant social activity in children with acute lymphoblastic leukemia is \hat p_1 = 1020/1272 = 85/106 = 0.8\overline {0188679245283} ≈ 0.802

The proportion of children with significant social activity in children without acute lymphoblastic leukemia is \hat p_2 = 5343/6238 ≈ 0.8565

c) We have the following two way table;

\begin{array}{ccc}Lymphoblastic \ Leukemia &With \ Social \ Activity & Without \ Social \ Activity\\With&1020 \ (a)&252 \ (b)\\Without&5343 \ (c)&895 \ (d) \end{array}

The \ odds \ ratio = \dfrac{1,020 \times 895}{5,343 \times 252} \approx 0.6780

The odds ratio ≈ 0.6780

d) The 95% confidence interval for the odds ratio is given as follows;

95 \% \ CI = OR \ \pm \ 1.96 \times \sqrt{\dfrac{1}{a} +\dfrac{1}{b}+\dfrac{1}{c}+\dfrac{1}{d}}

Where;

a = 1020, b = 252, c = 5343, d = 895

Therefore;

95 \% \ CI \approx  0.6780 \ \pm \ 1.96 \times \sqrt{\dfrac{1}{1,020} +\dfrac{1}{252}+\dfrac{1}{5,343}+\dfrac{1}{895}} \approx 0.678 \pm0.155

The 95% CI ≈ 0.523 < OR < 0.833

e) i) Given that the observed Odds Ratio is within the Confidence Interval, therefore, there is an indication that the amount of social activity is associated with acute lymphoblastic leukemia

ii) Based on the proportion of the study findings, children with more social activity have a higher occurrence of acute lymphoblastic leukemia

6 0
3 years ago
A point in rectangular coordinates is given. Convert the point to polar coordinates. Round your answers to two decimal places.
postnew [5]

Answer:

(√74, 54.46°)

Step-by-step explanation:

The rectangular coordinate point is given as; (5, 7)

Now, converting rectangular coordinates to polar coordinates is done by;

(r, θ)

Where, r is the magnitude while θ is the angle

r = √(5² + 7²)

r = √74

tan θ = (7/5)

θ = tan^(-1) 1.4

θ = 54.46°

Thus,polar coordinate is; (√74, 54.46°)

3 0
3 years ago
The figure undergoes a 90° rotation counterclockwise, followed by a reflection across a vertical line.
ollegr [7]

I am almost confident it is B

8 0
3 years ago
Read 2 more answers
Pls HELP WITH THESE TWO QUESTIONS NO LINKS
Marta_Voda [28]

Answer:

The answer to the first question is B.

The answer to the second question is C.

7 0
2 years ago
Read 2 more answers
Find the area of a rectangle whose perimeter is 60in and width is 10in.
Dafna1 [17]

Answer:

250 sq. inch

Step-by-step explanation:

Perimeter: 60 inch

: 2 X L+B

: 2 X ? + 10

Length: 60-10

: 50/2

: 25 inch

Area: L X B

: 25 X 10

: 250 sq.inch

Hope it helps ;)

Please tell if it's correct

Please mark as brainliest!

3 0
2 years ago
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