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3 years ago

Rename 4 thounsands 7 hundreds

Mathematics

2 answers:

algol [13]3 years ago

8 0

4,700 hoped I helped

NikAS [45]3 years ago

8 0

4,700 is it renamed

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The estimated daily living costs for an executive traveling to various major cities follow. The estimates include a single room

Alexandra [31]

Answer:

$\bar x = 260.1615$

$\sigma = 70.69$

The confidence interval of standard deviation is: $53.76$ to $103.25$

Step-by-step explanation:

Given

$n =20$

See attachment for the formatted data

Solving (a): The mean

This is calculated as:

$\bar x = \frac{\sum x}{n}$

So, we have:

$\bar x = \frac{242.87 +212.00 +260.93 +284.08 +194.19 +139.16 +260.76 +436.72 +355.36 +.....+250.61}{20}$

$\bar x = \frac{5203.23}{20}$

$\bar x = 260.1615$

$\bar x = 260.16$

Solving (b): The standard deviation

This is calculated as:

$\sigma = \sqrt{\frac{\sum(x - \bar x)^2}{n-1}}$

$\sigma = \sqrt{\frac{(242.87 - 260.1615)^2 +(212.00- 260.1615)^2+(260.93- 260.1615)^2+(284.08- 260.1615)^2+.....+(250.61- 260.1615)^2}{20 - 1}}$ $\sigma = \sqrt{\frac{94938.80}{19}}$

$\sigma = \sqrt{4996.78}$

$\sigma = 70.69$ --- approximated

Solving (c): 95% confidence interval of standard deviation

We have:

$c =0.95$

So:

$\alpha = 1 -c$

$\alpha = 1 -0.95$

$\alpha = 0.05$

Calculate the degree of freedom (df)

$df = n -1$

$df = 20 -1$

$df = 19$

Determine the critical value at row $df = 19$ and columns $\frac{\alpha}{2}$ and $1 -\frac{\alpha}{2}$

So, we have:

$X^2_{0.025} = 32.852$ ---- at $\frac{\alpha}{2}$

$X^2_{0.975} = 8.907$ --- at $1 -\frac{\alpha}{2}$

So, the confidence interval of the standard deviation is:

$\sigma * \sqrt{\frac{n - 1}{X^2_{\alpha/2} }$ to $\sigma * \sqrt{\frac{n - 1}{X^2_{1 -\alpha/2} }$

$70.69 * \sqrt{\frac{20 - 1}{32.852}$ to $70.69 * \sqrt{\frac{20 - 1}{8.907}$

$70.69 * \sqrt{\frac{19}{32.852}$ to $70.69 * \sqrt{\frac{19}{8.907}$

$53.76$ to $103.25$

8 0

2 years ago

Can someone please help with this math question:)

Bingel [31]

Solution:

The rationalisation factor for $\frac{1}{ a - \sqrt{b} }$ is $a + \sqrt{b}$

So, let us apply it here.

$\frac{1}{5 - \sqrt{2} }$

The rationalising factor for 5 - √2 is 5 + √2.

Therefore, multiplying and dividing by 5 + √2, we have

$= \frac{1}{5 - \sqrt{2} } \times \frac{5 + \sqrt{2} }{5 + \sqrt{2} } \\ = \frac{5 + \sqrt{2} }{(5 - \sqrt{2})(5 + \sqrt{2} ) } \\ = \frac{5 + \sqrt{2} }{ {(5)}^{2} - ( \sqrt{2})^{2} } \\ = \frac{5 + \sqrt{2} }{25 - 2} \\ = \frac{5 + \sqrt{2} }{23}$

Answer:

$\frac{5 + \sqrt{2} }{23}$

Hope you could understand.

If you have any query, feel free to ask.

5 0

2 years ago

Read 2 more answers

Please it's urgent I really need answers

WITCHER [35]

(c)

We notice that they already have common denominators, therefore we can just add the numerators up.

(x+y+x-y)/2xy=

2x/2xy

Dividing both top and bottom by 2x, we get

-Hunter

5 0

2 years ago

Read 2 more answers

4. A Pelican was flying 3 feet above sea level, when it dove to catch a fish that was 2 feet below sea level. How far did the pe

Alenkasestr [34]

Answer: The pelican dove 5ft

Step-by-step explanation:

Pelican = 3ft

Fish = -2ft

Went down 3ft to get to 0, went down 2 more feet to get the fish.

4 0

2 years ago

Can someone explain 5. please ?

GuDViN [60]

Both denominators are 4, so we can add the numerators to place over the common denominator. The numerators are -3 and -3, which add to -6. One way to think of negative numbers is to think of IOUs, which are a way of expressing debt in money. For instance, if you go into a store and buy a $10 item, but only have $3 in your pocket, then you would have to owe the owner $7. This can be represented with -7. If you repeat the process, then you'd have 7+7 = 14 in IOUs total. This would be represented with -14

In short, adding negative numbers is really the same as adding positives, but the final result is negative

So that's why -3+-3 turns into -6. We add the two threes like normal but then make the final result negative. All throughout this process, the denominator stays at 4.

So we end up with -6 over 4 which reduces to -3 over 2. How is this reduction happening? We are simply dividing each piece by the greatest common factor 2.

-6 divided by 2 = -3

4 divided by 2 = 2

5 0

3 years ago