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2 years ago

PLS HELP!!!!! I WILL GIVE BRAINLEST JUST PLS HELP!!!

Mathematics

1 answer:

steposvetlana [31]2 years ago

5 0

Answer:

Step-by-step explanation:

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"a pollster wishes to estimate the number of left-handed scientists. how large of a sample is needed in order to be 98% confiden

nadezda [96]

The sample size should be 250.

Our margin of error is 4%, or 0.04. We use the formula

$\text{ME}=z\sqrt{\frac{\hat{p}(1-\hat{p})}{n}}$

To find the z-score:
Convert 98% to a decimal: 0.98
Subtract from 1: 1-0.98 = 0.02
Divide both sides by 2: 0.02/2 = 0.01
Subtract from 1: 1-0.01 = 0.99

Using a z-table (http://www.z-table.com) we see that this value has a z-score of approximately 2.33. Using this, our margin of error and our proportion, we have:

$0.04=2.33\sqrt{\frac{0.08(1-0.08)}{n}}
\\
\\0.04=2.33\sqrt{\frac{0.08(0.92)}{n}}$

Divide both sides by 2.33:
$\frac{0.04}{2.33}=\sqrt{\frac{0.08(0.92)}{n}}$

Square both sides:
$(\frac{0.04}{2.33})^2=\frac{0.08(0.92)}{n}$

Multiply both sides by n:
$(\frac{0.04}{2.33})^2n=0.08(0.92)$

Divide both sides to isolate n:
$\frac{0.08(0.92)}{(\frac{0.04}{2.33})^2}=n
\\
\\249.73=n
\\n\approx 250$

4 0

3 years ago

Kay has 28 coins which includes nickels and dimes if the total is 2.35$, how many of each coin does Kay have?

BaLLatris [955]

Answer:

19 dimes and 9 nickels

Step-by-step explanation:

Model the situation using two equations, then solve the system.

let n be number of nickels and d be number of dimes.

n + d = 28 <= This equation is about the number of coins.

0.05n + 0.10d = 2.35 <=This equation is about the worth in dollars.

Rearrange n + d = 28.

n = 28 - d

Now we can substitute this equation into the other one.

Sub n =28-d at the "d" variable for the equation 0.05n + 0.10d = 2.35

0.05n + 0.10d = 2.35

Now there is only one variable.

0.05(28 - d) + 0.10d = 2.35 <=distribute this

0.05(28 - d) + 0.10d = 2.35

1.4 - 0.05d + 0.10d = 2.35 <=combine like terms

1.4 + 0.05d = 2.35 <= begin to isolate d

0.05d = 2.35 - 1.4

0.05d = 0.95

d = 0.95/0.05

d = 19

Now that we know d=19, we can substitute it into any equation.

Choose the equation n + d = 28 because the numbers are easier.

n + d = 28

n + 19 = 28 <=isolate n

n = 28 - 19

n = 9

Since n=9 and d=19, Kay has 9 nickels and 19 dimes.

8 0

3 years ago

Read 2 more answers

Subtract. 29.82 − 8.001 The difference is

maks197457 [2]

Answer:

21.819 is the difference

8 0

3 years ago

Drag the tiles to the correct boxes to complete the pairs. Not all tiles will be used.

yan [13]

Answer:

1. ║u-z║= 5.66

2.║v-w║=6.0

3. ║w-u║=6.08

4.║v-u║=7.81

Step-by-step explanation:

The vectors are given as;

u = <-1, -3>, v = <5,-8>, w = <5, -2>, and z = <3, 1>.

To find the magnitude of the vectors;

1. ║u-z║

<-1 - 3> = <-4 and < -3 - 1> = <-4

║<-4,-4> ║= √{ -4²+-4²} = √32 = 5.66

2.║v-w║

<5,-8> - <5,-2>

<5-5> , <-8--2>

<0,-6>

║<0,-6>║= √{0²+ -6²} = √36 = 6

3. ║w-u║

<5,-2> - <-1,-3>

<5--1> , <-2--3>

<6,1>

║6,1║= √{6²+1²} = √36+1 = √37 = 6.08

4.║v-u║

<5,-8> - <-1,-3>

<5--1> , <-8--3>

< 6 , -5 >

║6,-5║= √{6²+-5²} = √36+25 =√61 = 7.81

5 0

3 years ago

Help please no links!!This is my concluding answer let me know if it's right or wrong please!!

Amanda [17]

yeah i guess you re right sorry for making confusion

6 0

3 years ago