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anzhelika [568]
3 years ago
12

How many weeks of data must be randomly sampled to estimate the mean weekly sales of a new line of athletic footwear? We want 98

% confidence that the sample mean is within $400 of the population mean, and the population standard deviation is known to be $1400.
Mathematics
1 answer:
Irina18 [472]3 years ago
8 0

Answer:

n=(\frac{2.33(1400)}{400})^2 =66.50 \approx 67

So the answer for this case would be n=67 rounded up

Step-by-step explanation:

Information given

\bar X represent the sample mean for the sample  

\mu population mean

\sigma=1400 represent the sample standard deviation

n represent the sample size  

Solution to the problem

The margin of error is given by this formula:

ME=z_{\alpha/2}\frac{\sigma}{\sqrt{n}}    (a)

And on this case we have that ME =400 and we are interested in order to find the value of n, if we solve n from equation (a) we got:

n=(\frac{z_{\alpha/2} \sigma}{ME})^2   (b)

The critical value for 98% of confidence interval now can be founded using the normal distribution. And the critical value would be z_{\alpha/2}=2.33, replacing into formula (b) we got:

n=(\frac{2.33(1400)}{400})^2 =66.50 \approx 67

So the answer for this case would be n=67 rounded up

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Slope of 5,2 and 6,2
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Answer:

The slope is 0

Step-by-step explanation:

(2-2) divided by (6-5) equals to 0 which is the Slope

\frac{2-2}{6-2} \\\\

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3 years ago
3[-x + (2 x + 1)] = x - 1<br><br> what is x
lubasha [3.4K]

Answer:

the answer is x=-2 as answer

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2 years ago
What is 1/5 of 30????
igor_vitrenko [27]
1/5 of 30 is 6!
In order to find this you do
1/5 x 30
Answer: 6
5 0
3 years ago
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Pls help! 50 POINTS!
nirvana33 [79]

Answer:

See below.

Step-by-step explanation:

1)

So we have the equation:

2x+3y=1470

To change into the slope-intercept form, we need to isolate the y-variable. Thus, subtract 2x from both sides:

(2x+3y)-2x=(1470)-2x

The left side cancels:

3y=1470-2x

Now, divide both sides by 3. The left side cancels:

(3y)/3=(-2x+1470)/3\\y=-\frac{2}{3} x+490

The slope-intercept form is:

y=mx+b

Where m is the slope and b is the y-intercept.

Thus, the slope is -2/3 and the y-intercept is 490.

2)

So, since we already know the y-intercept is 490, plot a point at (0,490).

The slope is too small to use. Thus, multiply the fraction by 100. It is now (-200/300). This means that we move <em>down</em> 200 for every 300 (recall that the slope means rise over run. Thus, we move down 200 for every 300 to the right). Thus, another possible point would be (0+300,490-200) or (300,290). Plot that. Then, connect them.

3)

To write in in function notation, simply substitute the y-variable for the function notation. Our independent variable here is x so we'll use that.

y=-\frac{2}{3}x+490\\ f(x)=-\frac{2}{3}x+490

This means that for every x sandwiches made, there is f(x) wraps made for the total sum to be $1,470.

For example, if 105 sandwiches were made, then f(105)=-2/3(105)+490=420 wraps were made for the total profit to be $1,470.

4)

Please refer to the attached graph.

5)

First, since the total profit has now increased, the graph above and to the right of the old graph. This is because Sal needs to sell more sandwiches and wraps. Likewise, because of this, the x- and y-intercepts will also be different. Nevertheless, if converted into the slope-intercept equation, the slope will remain the same.

5 0
3 years ago
Read 2 more answers
Two​ trains, Train A and Train​ B, weigh a total of 489 tons. Train A is heavier than Train B. The difference of their weights i
makvit [3.9K]

Answer:

Weight of Train A = 454 tons

Weight of Train B = 35 tons

Step-by-step explanation:

It is given that:

Let,

A represent weight of Train A

B represent weight of Train B

According to given information:

A + B = 489      Eqn 1

A - B = 419       Eqn 2

Adding Eqn 1 and 2

A + B + A - B = 489 + 419

2A = 908

Dividing both sides by 2

\frac{2A}{2}=\frac{908}{2}\\A = 454

Putting A = 454 in Eqn 1

454 + B = 489

B = 489 - 454

B = 35

Therefore,

Weight of Train A = 454 tons

Weight of Train B = 35 tons

5 0
2 years ago
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