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aalyn [17]
3 years ago
6

Is smoking during pregnancy associated with premature births? To investigate this question, researchers selected a random sample

of 123 pregnant women who were smokers. The average pregnancy length for this sample of smokers was 262 days. From a large body of research, it is known that length of human pregnancy has a standard deviation of 16 days. The researchers assume that smoking does not affect the variability in pregnancy length.
Find the 99% confidence interval to estimate the length of pregnancy for women who smoke.

(Note: The critical
z
-value to use,
z
c
, is: 2.576)

( , )

Your answer should be rounded to 3 decimal places.
Mathematics
1 answer:
topjm [15]3 years ago
7 0

Answer:

C

Step-by-step explanation

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Does someone mind helping me with this problem? Thank you!
g100num [7]

Answer:

area = 1/2 b*h

Step-by-step explanation:

1/2 * 6 * 8 = 24 ft^2

4 0
2 years ago
Read 2 more answers
Write the equation of a line that is parallel to 4x-2y=3 and is passing through the point (2,1)
Temka [501]

Answer:

y= 2x -3

Step-by-step explanation:

Let's rewrite the given equation into the form of y=mx+c, so that we can find the gradient of the line. In this form, m (coefficient of x) is the gradient.

4x -2y= 3

2y= 4x -3

<em>Divide</em><em> </em><em>by</em><em> </em><em>2</em><em> </em><em>throughout</em><em>:</em>

y = 2x - 1 \frac{1}{2}

Thus the gradient is 2.

Parallel lines have the same gradient thus the line would also have a gradient of 2.

Substitute m=2 into the equation:

y= 2x +c

To find the value of c, substitute a pair of coordinates.

When x=2, y=1,

1= 2(2) +c

1= 4 +c

c= 1 -4

c= -3

Thus, the equation of the line is y= 2x -3.

5 0
3 years ago
HELP PLZ GUYS I BEG YOU 15 PTS ITS EASYYYYYYY!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Aliun [14]

Answer:

1) The linear equation in point and slope form is y - 67 = -4 × (x - 14)

2) The variables are;

a) The number of candies available = y

b) The number of days Jennifer eats the candies =

c) The slope, m = -4

3) Jennifer received 123 pieces of candies on Halloween

Step-by-step explanation:

The given parameters are;

The number of candies Jennifer eats everyday = 4 pieces

The number of days for which Jennifer eats the daily 4 candies = 14

The number of candies left at the end of the 14th day = 67 candies

1) We note that the rate of decrease in the number of candies = 4 candies/day

Therefore, the slope of the linear equation is m = -4

The y-intercept = The initial amount of candies Jennifer has = c = 67 + 14× 4 = 123 candies

The linear equation in point and slope form is given as follows;

y - 67 = -4 × (x - 14)

2) The variables are;

a) The y-value represents the number of candies available on a specific day

b) The x value represents the number of days Jennifer eats the candies'

c) The slope = The rate of decrease in the number of candies per day = -4

3) The number of candies Jennifer receives on Halloween is given by the y-intercept of the straight line equation as follows;

y - 67 = -4 × (x - 14)

y - 67 = -4·x + 56

y = -4·x + 56 + 67 = -4·x + 123

y = -4·x + 123

Comparing the above equation, with the general form of the straight line equation, y = m·x + c, where, the constant term, c = The y-intercept, we have;

The y-intercept of the equation y = -4·x + 123 = 123 = The initial amount of candies Jennifer received on Halloween.

6 0
3 years ago
Some investments in the stock market have earned 10% annually. At this rate , earnings can be found using the formua A=P(1.10)^n
Lerok [7]
<span>The earnings by a stock invested at r% for n years is obtained by the formular A = P(1 + r)^n; where P is the initial investment = 1,500; r is the interest rate = 10% and n is the numberof years of the investment. Here A = 1,500(1 + 0.1)^18 = 1,500(1.1)^18 = 8,339.88.Hope this helps. Let me know if you need additional help!</span>
8 0
4 years ago
Read 2 more answers
Find the real numbers x and y if -3+ix^2y and x^2+y+4i are conjugate of each other. Pls solve with the steps
Firdavs [7]
ANSWER
x = ±1 and y = -4.
Either x = +1 or x = -1 will work

EXPLANATION
If -3 + ix²y and x² + y + 4i are complex conjugates, then one of them can be written in the form a + bi and the other in the form a - bi. In other words, between conjugates, the imaginary parts are same in absolute value but different in sign (b and -b). The real parts are the same

For -3 + ix²y
⇒ real part: -3
⇒ imaginary part: x²y

For x² + y + 4i
⇒ real part: x² + y (since x, y are real numbers)
⇒ imaginary part: 4

Therefore, for the two expressions to be conjugates, we must satisfy the two conditions. 

Condition 1: Imaginary parts are same in absolute value but different in sign. We can set the imaginary part of -3 + ix²y to be the negative imaginary part of x² + y + 4i so that the 

   x²y = -4 ... (I)

Condition 2: Real parts are the same

   x² + y = -3 ... (II)

We have a system of equations since both conditions must be satisfied

   x²y = -4 ... (I)
   x² + y = -3 ... (II)

We can rearrange equation (II) so that we have

   y = -3 - x² ... (II)

Substituting into equation (I)

   x²y = -4 ... (I)
   x²(-3 - x²) = -4
   -3x² - x⁴ = -4
   x⁴ + 3x² - 4 = 0
   (x² + 4)(x² - 1) = 0
   (x² + 4)(x-1)(x+1) = 0

Therefore, x = ±1.
Leave alone (x² + 4) as it gives no real solutions.

Solve for y:

   y = -3 - x² ... (II)
   y = -3 - (±1)²
   y = -3 - 1
   y = -4

So x = ±1 and y = -4. We can confirm this results in conjugates by substituting into the expressions:

   -3 + ix²y 
   = -3 + i(±1)²(-4)
   = -3 - 4i

   x² + y + 4i
   = (±1)² - 4 + 4i
   = 1 - 4 + 4i
   = -3 + 4i

They result in conjugates
4 0
3 years ago
Read 2 more answers
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