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4 years ago

Question 3 a and b I need help with please

Mathematics

1 answer:

Nookie1986 [14]4 years ago

8 0

For a, assuming that you will be spraying all sides of the cushions, including the side facing down, you need to figure out the total surface area for the cushion. The formula is 2(lw + wh + hl). l = length, w = width, h = height. Once you do that, then you will need to multiply that number by six because there are six cushions. This number will be in sq. centimeters. Next you need to convert the coverage area of the spray from sq meters to sq centimeters ( m = 1000cm). Now you will take your total surface area of the six cushions and divide it by the number of sq. centimeters that one can of spray covers and that will give you the number of cans needed.

For b, you will take the number of sq centimeters per a can and multiply by 10% (.10), then add that number to the original can amount. Now you will take the total surface area of the six cushions and divide it by the 10% more amount you just calculated to find out how many cans are needed. This answer should be a smaller number than the number of cans calculated for answer a.

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Find the 95% confidence interval for estimating the population mean μ

AVprozaik [17]

We first need to determine whether we are dealing with means or proportions in this problem. Since we are given the sample and population mean, we know that we are dealing with means.

Since we have one sample mean, this means we are creating a confidence interval for one sample (1 Samp T Int).

Normally we would check for conditions, but since this is not formulated as a "real-world scenario" type problem, it is hard to check for randomness and independence. Therefore, I will be excluding conditions from this answer.

<h3>Confidence Interval Formula</h3>

The formula for constructing a <u>confidence interval for means</u> is as follows:

$\displaystyle \overline{x} \pm t^*\big{(}\frac{\sigma}{\sqrt{n} } \big{)}$

We are given these variables:

$\overline{x}=50$
$n=60$
$\sigma=10$

Plug these values into the formula for the confidence interval:

$\displaystyle 50\pm t^* \big{(}\frac{10}{\sqrt{60} } \big{)}$

<h3>Finding the Critical Value (t*)</h3>

In order to find t*, we can use this formula:

$\displaystyle \frac{1-C}{2}=A$

Calculating the z-score associated with "A" will give us t*.

So, let's plug in the confidence interval 95% (.95) into the formula:

$\displaystyle \frac{1-.95}{2}=.025$

Use your calculator or a t-table to find the z-score associated with this area under the curve.. you should get:

$t^*=1.96$

<h3>Constructing Confidence Interval</h3>

Now, let's finish the confidence interval we created:

$\displaystyle 50\pm 1.96 \big{(}\frac{10}{\sqrt{60} } \big{)}$

We can calculate the confidence interval, using this formula, to be:

$\boxed{(47.4697, \ 52.5303)}$

<h3>Interpreting the Confidence Interval</h3>

We are 95% confident that the true population mean μ lies between <u>47.4697 and 52.5303</u>.

8 0

2 years ago

What number is 40% of 720

Zarrin [17]

You would have to set you problem up like
x 40
____=_____
720 100

you would multiply 40 by 720 then you would divide 28,800 by 100 your answer will be 288.

3 0

3 years ago

Leticia charges 8$ per hour to babysit. She babysat Friday night for 4 hours ,and then she babysat again on saturday.She earned

BaLLatris [955]

Leticia babysat on Saturday for 5 hours. She already babysat for 4 hours which makes it (8 x 4) =$32 But she earned $72 so the rest $40 / 8 =5 hours

4 0

3 years ago

If x=0. Find the value of 8x-2(6-x)

Harrizon [31]

Answer:

-12

Step-by-step explanation:

8x - 2(6 - x)

Substitute 0 for each x

8*0 - 2(6 - 0)

Solve.

0 - 2*6

0 - 12

-12

7 0

3 years ago

Read 2 more answers

Please help. I don't understand anything.

alina1380 [7]

Answer:

Step-by-step explanation:

The area of figure=Area of rectangle+Area of triangle

Area of figure=(x+2)(x-3)+1/2*(x)*(x+2)

Area of figure=x^2-x-6+0.5*x^2+x

Area of figure=(3/2)x^2-6

7 0

3 years ago

Read 2 more answers