Plz help this question out

A clinical trial tests a method designed to increase the probability of conceiving a girl. In the study 290 babies were born, a

Ne4ueva [31]

Answer:

The 99% confidence interval estimate of the percentage of girls born is between 85.46% and 94.54%.

Usually, babies are equally as likely to be boys or girls. Here, it is desired to increase the probability of conceiving a girl, which is achieved, considering the lower bound of the confidence interval is considerably above 50%.

Step-by-step explanation:

Confidence interval for the proportion:

In a sample with a number n of people surveyed with a probability of a success of $\pi$ , and a confidence level of $1-\alpha$ , we have the following confidence interval of proportions.

$\pi \pm z\sqrt{\frac{\pi(1-\pi)}{n}}$

In which

z is the zscore that has a pvalue of $1 - \frac{\alpha}{2}$ .

For this problem, we have that:

$n = 290, \pi = \frac{261}{290} = 0.9$

99% confidence level

So $\alpha = 0.01$ , z is the value of Z that has a pvalue of $1 - \frac{0.01}{2} = 0.995$ , so $Z = 2.575$ .

The lower limit of this interval is:

$\pi - z\sqrt{\frac{\pi(1-\pi)}{n}} = 0.9 - 2.575\sqrt{\frac{0.9*0.1}{290}} = 0.8546$

The upper limit of this interval is:

$\pi + z\sqrt{\frac{\pi(1-\pi)}{n}} = 0.9 + 2.575\sqrt{\frac{0.9*0.1}{290}} = 0.9454$

Percentage:

Proportion multplied by 100.

0.8546*100 = 85.46%

0.9454*100 = 94.54%

The 99% confidence interval estimate of the percentage of girls born is between 85.46% and 94.54%.

Based on the result, does the method appear to be effective?

Usually, babies are equally as likely to be boys or girls. Here, it is desired to increase the probability of conceiving a girl, which is achieved, considering the lower bound of the confidence interval is considerably above 50%.

4 0

3 years ago

Easy Question pls help. (Algebra II type problems)

Roman55 [17]

Answer:

$\large\boxed{if\ x\neq-3\ \wedge\ y\neq0\ \wedge\ x\neq y\ \wedge\ x\neq -y}$

second

$\large\boxed{y\neq0\ \wedge\ x\neq-y\ (y\neq-x)}$

Step-by-step explanation:

We know that dividing by 0 is impossible.

Therefore, the denominator of the expression must be different from 0.

$\text{For}\\\\\dfrac{(x-y)^2}{2xy+6y}\times\dfrac{4x+12}{x^2-y^2}\\\\\\2xy+6y\neq0\qquad(1)\\\\x^2-y^2\neq0\qquad(2)$

$(1)\\2xy+6y\neq0\qquad\text{distribute}\\\\2y(x+3)\neq0\iff2y\neq0\ \wedge\ x+3\neq0\\\\2y\neq0\qquad\text{divide both sides by 2}\\\boxed{y\neq0}\\\\x+3\neq0\qquad\text{subtract 3 from both sides}\\\boxed{x\neq-3}\\==========================\\(2)\\x^2-y^2\neq0\qquad\text{use}\ a^2-b^2=(a-b)(a+b)\\(x-y)(x+y)\neq0\iff x-y\neq0\ \wedge\ x+y\neq0\\\boxed{x\neq y}\ \wedge\ \boxed{x\neq-y}$

$\text{For}\\\\\dfrac{2(x-y)}{y(x+y)}\\\\y(x+y)\neq0\iff y\neq0 \wedge\ x+y\neq0\\\\ \boxed{y\neq0}\ \wedge\ \boxed{x\neq-y}$

3 0

3 years ago

What are the dimensions of a rectangle with a perimeter of 70 and a length to width ratio of 4 to 5?

nasty-shy [4]

Hello :
let : x the length and y the <span>width
the perimeter is : 2(x+y)
2(x+y) = 70 and : x/y =4/5
x+y = 35 ......(1)
x = (4/5)y ... (2)
subsct in : (1)
</span> (4/5)y +y = 35
4y+5y = 175
9y = 175
y = 175/9
in (2) : x = (4/5)(175/9) = 140/9

4 0

3 years ago

mandy finished editing 38% of a book in 5 days. if the book is 300 hundred pages long how many pages did mandy edit so far

Roman55 [17]

Answer:

380 pages

Step-by-step explanation:

because if 30% equals 300 means 38% equals 380

6 0

3 years ago

Read 2 more answers

I WILL MARK BRAINLIEST <br><br> PLEASE SHOW WORK

Serhud [2]

Answer:

V =91.125 in ^3

Step-by-step explanation:

The volume of a cube is given by

V = s^3 where s is the side length

V= 4.5 ^ 3

V =91.125 in ^3

4 0

4 years ago

Read 2 more answers