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2 years ago

Please help I don't understand this

Mathematics

1 answer:

xxTIMURxx [149]2 years ago

3 0

3r^2 = 3 x r^2 = 3 x 1/6^2 = 3 x 1/36 = 3/36 = 1/12

Answer:
1/12

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The number of motor vehicles registered in millions in the US has grown as follows:

zysi [14]

Answer:

a) Figure attached

b) $r=\frac{n(\sum xy)-(\sum x)(\sum y)}{\sqrt{[n\sum x^2 -(\sum x)^2][n\sum y^2 -(\sum y)^2]}}$

For our case we have this:

n=10 $\sum x = 75.819, \sum y = 43.5231, \sum xy = 330.0321, \sum x^2 =574.8598, \sum y^2 =192.8274$

$r=\frac{10(330.0321)-(75.81948)(43.5231)}{\sqrt{[10(574.8598) -(75.819)^2][10(192.8274) -(43.5231)^2]}}=0.989$

So then the correlation coefficient would be r =0.989

Step-by-step explanation:

Previous concepts

The correlation coefficient is a "statistical measure that calculates the strength of the relationship between the relative movements of two variables". It's denoted by r and its always between -1 and 1.

Solution to the problem

Part a

Year (x): 1940, 1945 1950, 1955, 1960, 1965, 1970, 1975, 1980, 1985

Vehicles (Y): 32.4, 31.0, 49.2, 62.7, 73.9, 90.4, 108.4, 132.9, 155.8, 171.7

After apply natural log for the two variables and create the scatterplot in excel we got the following result on the figure attached.

Part b

And in order to calculate the correlation coefficient we can use this formula:

$r=\frac{n(\sum xy)-(\sum x)(\sum y)}{\sqrt{[n\sum x^2 -(\sum x)^2][n\sum y^2 -(\sum y)^2]}}$

For our case we have this:

n=10 $\sum x = 75.819, \sum y = 43.5231, \sum xy = 330.0321, \sum x^2 =574.8598, \sum y^2 =192.8274$

$r=\frac{10(330.0321)-(75.81948)(43.5231)}{\sqrt{[10(574.8598) -(75.81948)^2][10(192.8274) -(43.5231)^2]}}=0.989$

So then the correlation coefficient would be r =0.989

4 0

2 years ago

A study of the career paths of hotel general managers sent questionnaires to an SRS of 160 hotels belonging to major U.S. hotel

otez555 [7]

Answer:

(10.78483, 12.61517)

Step-by-step explanation:

It is given that the genera mangers of few hotels were sent some questionnaires for conducting a study for the career paths in the major hotel chains of the United States.

Number of hotels = 160

Number of response received = 103

The average number of years these general mangers was in their current hotels, $\bar x$ = 11.7 years

Confidence Interval, CI = 0.99

Therefore,

a = 0.01, |Z(0.005)| (from standard normal table)

∴ 99% of CI = $\bar x \pm Z \times \frac{s}{\sqrt n}$

$= 11.7 \pm 2.58 \times \frac{3.6}{\sqrt {103}}$

$(10.78483, 12.61517)$

3 0

3 years ago

Can someone please help me with this question?

saw5 [17]

(0, 9) represents the y-intercept of the graph.

Since the slope is 1/3, this means that y will rise 1 for every 3 that x runs.

The points that can be used to make a line in this graph are (3, 10) and (6, 11).

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3 years ago

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Join for a maths intervention-foundation

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Answer:

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