Read the below scenario and then answer the questions that follow. The Ancestry Society of North Carolina is compiling records so they can learn about the history of African Americans in North Carolina from 1820 to 1980. They have complied records of all 15,125 gravestones in cemeteries across all 15 counties. They want to choose a sample of 600 records to check their accuracy by visiting the actual gravestones.
a) Using the hat method explain how they could gather a simple random sample of 600 gravestones to visit.
b) Explain why it would be better to take a sample 40 gravestones from all 15 counties.
c) For what population could they make inference about after gathering and examining the sample?

Answer:

[0.6969, 0.7695]

Step-by-step explanation:

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

[tex]\pi \pm z\sqrt{\frac{\pi(1-\pi)}{n}}[/tex]

In which

z is the z-score that has a p-value of [tex]1 - \frac{\alpha}{2}[/tex].

They randomly survey 401 drivers and find that 294 claim to always buckle up.

This means that [tex]n = 401, \pi = \frac{294}{401} = 0.7332.

90% confidence level

So [tex]\alpha = 0.1[/tex], z is the value of Z that has a p-value of [tex]1 - \frac{0.1}{2} = 0.95[/tex], so [tex]Z = 1.645[/tex].  

The lower limit of this interval is:

[tex]\pi - z\sqrt{\frac{\pi(1-\pi)}{n}} = 0.7332 - 1.645\sqrt{\frac{0.7332*0.2668}{401}} = 0.6969[/tex]

The upper limit of this interval is:

[tex]\pi + z\sqrt{\frac{\pi(1-\pi)}{n}} = 0.7332 + 1.645\sqrt{\frac{0.7332*0.2668}{401}} = 0.7695[/tex]

The 90% confidence interval for the population proportion that claim to always buckle up is [0.6969, 0.7695]

Answer:

answer is 12

Step-by-step explanation:

gcf = 3

lcm = 180

let 45 be y

let unknown be X

to get x

X=( lcm * gcf) / y

X=(180*3)/45

X=(540)/45

X=12

the other number is 12

Answer:

(6C1)(5C1)/20C2

Step-by-step explanation:

Was right on egde

Answer:

37/43

Step-by-step explanation:

6+12+14+11=43

Males: 6+14=20

Females: 11+12=23

If the selected person is a teaching assistant or a female, then the probability is 11+12+14=37. 37/43

Answer:

<a=55° ,< b=55° and <c=70°

Answer:

theres no question....

Step-by-step explanation:

???

Answer:

F(t) = 9(1 + 0.13)^t

Step-by-step explanation:

Given :

Height of beanstalk = initial height = 9 inches

Percentage increase in height per day = 13%

This plant exhibits an exponential increase in growth per day, hence, the function will be modeled using an exponential function.

Using an exponential function :

F(t) = initial height(1 + percentage increase)^t

Where, t = number of days since tree was planted.

The function is :

F(t) = 9(1 + 0.13)^t

Answer:

3*10=30 gallons after 10 hours

minus 1 gal/hr for 5 hours=25 gallons.

If the animals are still drinking, the pool is effectively filling at 1 gal/hr, 2-1, and it will take 35 more hours to fill.

If the animals aren't drinking, the pool will fill at 2 gal/hour and it will be full in 35/2 hours or 17.5 hours.

Step-by-step explanation:

Answer:

∡A =41°

~~~~~~~~~~~~

BC=21

~~~~~~~~~~~~~~

sin(24)/AC=sin(41)/21

AC=13

~~~~~~~~~~~~~~

sin(115)/AB=sin(41)/21

AB=29

Step-by-step explanation:

Answer:

y+4=-3(x+8)

Step-by-step explanation:

Answer:

9/4

Step-by-step explanation:

f(x) is continuous and differentiable on (0,9).

We want to find c using the following equation.

f'(c)=(f(9)-f(0))/(9-0)

This will require us to find f'(x) first.

f(x)=sqrt(x) is the same as   f(x)=(x)^(1/2)

Using power rule to differentiate this gives f'(x)=(1/2)(x)^(1/2-1) or simplified f'(x)=(1/2)x^(-1/2) or f'(x)=1/(2x^(1/2)).

So we want to solve:

(1/2)c^(-1/2)=(f(9)-f(0))/(9-0)

Simplify denominator on right:

(1/2)c^(-1/2)=(f(9)-f(0))/9

This will require us to find f(9) and f(0).

If f(x)=sqrt(x), then f(9)=sqrt(9)=3 and f(0)=sqrt(0)=0.

So we have the following equation so far:

(1/2)c^(-1/2)=(3-0)/9

Simplify numerator on right:

(1/2)c^(-1/2)=3/9

Multiply both sides by 2:

c^(-1/2)=6/9

Raise both sides to the -2 power:

c^(1)=(6/9)^(-2)

Note c^1=c:

c=(6/9)^(-2):

Note negative exponent means to find reciprocal of base to change exponent to opposite

c=(9/6)^2

Apply the second power:

c=81/36

Reduce by dividing top and bottom by 9:

c=9/4

This means the slope of the tangent to the curve f at x=9/4 is the same value as the slope of the secant line going through points (0,0) and (9,3).

Also 9/4 is between 0 and 9... According to the theorem we were suppose to get a value c between x=0 and x=9.

Confirmation:

Slope of the secant line is (3-0)/(9-0)=3/9=1/3.

Slope of the tangent line to curve f at x=9/4.

f'(x)=(1/2)x^(-1/2)

f'(9/4)=(1/2)(9/4)^(-1/2)

f'(9/4)=(1/2)(3/2)^(-1)

f'(9/4)=(1/2)(2/3)

f'(9/4)=1/3

They are indeed equal values (talking about the 1/3 from the secant and the tangent.)

Answer:

D

Step-by-step explanation:

sqrt_{4}(81)^5=(81^(5))^(1/4)=81^(5/4)

Answer:

D

Step-by-step explanation:

if it was properly typed, it would have been All of the above but the most correct option is D.

9514 1404 393

Answer:

  A

Step-by-step explanation:

To form the conjugate, change the sign between terms. Leave the radical alone.

  the conjugate is √(x-5) +2 . . . . matches choice A

[tex]\huge\bold\pink{ANSWER} [/tex]

===========================================

A

[tex] \sqrt{ \times - 5 + 2} [/tex]

tsurezure children

#BrainliestBunch

Answer:

2cm

Step-by-step explanation:

area of parallelogram=b*h=18cm

5*4=20

length of corresponding heights=20-18

=2cm

the length of corresponding height of the parallelogram is : 2cm

A parallelogram can be defined as a simple quadrilateral that is it possesses four sides and two pairs of parallel sides.

A opposite sides of a parallelogram are equal and the opposite angles of a parallelogram are equal.

In conclusion, the length of corresponding height of the parallelogram is : 2cm

Learn more about  parallelogram : https://brainly.com/question/970600

#SPJ2

Answer:

45360 arrangements

Step-by-step explanation:

Given the word 'robberies'

Number of letters = 9 letters in total

Repeated letters ; r = 2 ; b = 2 ; e = 2

Therefore, the number of distinct arrangement of letters is :

(total letters)! / repeated letters!

The number of distinct arrangement of letters is :

9! / (2! * 2! * 2!) = (9*8*7*6*5*4*3*2*1) / (2*2*2)

362880 / 8 = 45360 arrangements

x= 55°

according to the picture .........

Answer: 85 i think

Step-by-step explanation:

Answer:

601 in²

Step-by-step explanation:

To obtain the amount of wrapping needed to cover the cube shaped gift box, including the bow

Area of bow = 115 in²

Surface area of cube shaped box = 6a²

a = side length of cube = 9

Hence,

Surface area of gift box = 6 * 9²

Surface area = 6 * 81 = 486 in²

Total wrapping required = area of gift box + area of bow = (486 in² + 115 in²) = 601 in²

144 x 1.25 = 180

Answer: 144

Answer:

144

Step-by-step explanation:

144 × 1.25 = 180

We add the 1 to .25 to represent the original value plus the 25% increase.

Or you could have divided 180 by 1.25 to find original price.

Answer:

They will blink together at 24minutes

Step-by-step explanation:

Using product of primes

4 = 2²

6 = 2 × 3

8 = 2³

Prime numbers with highest power

2³ × 3

8 x 3

24 minutes.

Answer:

B.

Step-by-step explanation:

The answer is B.

Answer:  

STEP 1  

M_{4,2} is set of 4x2 matrices hence each matrix has 4*2=8 entries. Each entry can be filled independently.  

Hence its basis has 8 linearly independent vectors.  

STEP 2  

Dimension= cardinality of basis = 8.

[tex]\huge\text{Hey there!}[/tex]

[tex]\mathsf{\dfrac{9}{10}+\dfrac{7}{15}}[/tex]

[tex]\large\textsf{FIRST: FIND the LCD (Lowest Common Denominator) then solve}\\\large\textsf{from there!}[/tex]

[tex]\large\textsf{If you have calculated it correctly, you should have came up with \underline{\bf 30}}\\\large\textsf{as your LCD (Lowest Common Denominator).}[/tex]

[tex]\mathsf{= \dfrac{9\times3}{10\times3}+ \dfrac{7\times2}{15\times2}}[/tex]

[tex]\mathsf{9\times3=\bf 27}\\\mathsf{10\times3=\bf 30}\\\\\mathsf{7\times2=\bf 14}\\\mathsf{15\times2=\bf 30}[/tex]

[tex]\mathsf{= \dfrac{27}{30}+\dfrac{14}{30}}[/tex]

[tex]\mathsf{= \dfrac{27+14}{30}}[/tex]

[tex]\mathsf{27+ 14=\bf 41}\\\\\mathsf{30+0=\bf 30}[/tex]

[tex]\mathsf{= \dfrac{41}{30}}\large\textsf{ which you could convert to }\mathsf{1 \dfrac{11}{30}}[/tex]

[tex]\boxed{\boxed{\large\textsf{ANSWER: }\bf \dfrac{41}{30} \large\textsf{ or }\mathsf{\bf 1 \dfrac{11}{30}\large\textsf{ because they both equal the same thing}}}}}\huge\checkmark[/tex]

[tex]\large\text{Good luck on your assignment and enjoy your day!}[/tex]

~[tex]\frak{Amphitrite1040:)}[/tex]

Answer: guess it your self

Step-by-step explanation:

Answer: SORRY NEED AN ACCOUNT ON - 10

Step-by-step explanation:

To resolve the proposed issue, an explanation is needed in which the subject is addressed

Answer:

the third option (a=1, h=0, k=6)

Step-by-step explanation:

if I understand correctly what your teacher wants from you, then you need find a (the factor of x² in the equation) and the vertex (turnaround point) of the parabola represented by such a quadratic equation.

the vertex point coordinates are called (h, k).

the general form of such an equation equation is

y = ax² + bx + c

so, we have a right away : a=1

now we can make this quickly by using common sense, or a bit more complex by going through mathematical formulas.

the fast, practical way is to know that y=x² is the very basic parabola with its vertex at (0, 0).

y = x² + 6 is simply the same parabola just lifted up (y direction) by 6 units, that makes the vertex (0, 6).

in pure theory, though, we need to find the transformation from the general y = ax² + bx + c form to

y = a(x - h)² + k

we see right away that k = f(h) = h² + 6

y = a(x² - 2xh + h²) + k

a=1

y = x² - 2xh + h² + k = x² - 2xh + h² + h² + 6 =

= x² - 2xh + 2h² + 6

comparing with y = x² + 6

we know that

-2×h = 0

as we have no term with just x.

=> h = 0

2h² + 6 = k

2×0² + 6 = 6 = k