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2 years ago

HELP ME FOR POINTS AND BRAINETEST

Mathematics

2 answers:

shutvik [7]2 years ago

8 0

Answer:

71.8 = 7 x 10 + 1 x 1 + 8 x 0.1

7.018 = 7 x 1 + 1 x 0.01 + 8 x 0.001

0.718 = 7 x 0.1 + 1 x 0.01 + 8 x 0.001

Step-by-step explanation:

Alexxandr [17]2 years ago

4 0

___________________________________________________________

Number 1 $>See Below$

$The\;second\;one,\; 7 *10+1*1+8*0.1$

___________________________________________________________

Number 2 $>See\;Below$

$The\;third\;one, 7*1+1*0.01+8*0.001$

___________________________________________________________

Number 3 $>See\;Below$

$The\;fourth\;one,\;7*0.1 + 1 * 0.01 + 8 * 0.001$

___________________________________________________________

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Answer:

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The taxi and takeoff time for commercial jets is a random variable x with a mean of 8.4 minutes and a standard deviation of 3.5

Lorico [155]

Answer:

0.6672 is the required probability.

Step-by-step explanation:

We are given the following information in the question:

Mean, μ = 8.4 minutes

Standard Deviation, σ = 3.5 minutes

We are given that the distribution of distribution of taxi and takeoff times is a bell shaped distribution that is a normal distribution.

According to central limit theorem the sum measurement of n is normal with mean $\mu$ and standard deviation $\sigma\sqrt{n}$

Sample size, n = 37

Standard Deviation =

$=\sigma\times \sqrt{n} = 3.5\times \sqrt{37}=21.28$

P(taxi and takeoff time will be less than 320 minutes)

$P( \sum x < 320) = P( z < \displaystyle\frac{320 - 37(8.4)}{21.28}) = P(z < 0.4323)$

Calculation the value from standard normal z table, we have,

$P(\sum x < 320) =0.6672 = 66.72\%$

0.6672 is the probability that for 37 jets on a given runway, total taxi and takeoff time will be less than 320 minutes.

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2 years ago

Solve the equation 3^(2x) -4*3^(x+1) + 27 = 0. use rules of exponents to change 3^(x+1)

Leviafan [203]

Answer:

$\huge\boxed{x=1\ \vee\ x=2}$

Step-by-step explanation:

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$\text{We return to substitution:}\\\\3^x=t\\\\3^x=3\ \vee\ 3^x=9\\\\3^x=3^1\ \vee\ 3^x=3^2\\\\\boxed{x=1}\ \vee\ \boxed{x=2}$

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2 years ago

An automobile dealer wants to see if there is a relationship between monthly sales and the interest rate. A random sample of 4 m

SVETLANKA909090 [29]

Answer:

a) $y=-6.254 x +75.064$

b) r =-0.932

The % of variation is given by the determination coefficient given by $r^2$ and on this case $-0.932^2 =0.8687$ , so then the % of variation explained by the linear model is 86.87%.

Step-by-step explanation:

Assuming the following dataset:

Monthly Sales (Y) Interest Rate (X)

22 9.2

20 7.6

10 10.4

45 5.3

Part a

And we want a linear model on this way y=mx+b, where m represent the slope and b the intercept. In order to find the slope we have this formula:

$m=\frac{S_{xy}}{S_{xx}}$

Where:

$S_{xy}=\sum_{i=1}^n x_i y_i -\frac{(\sum_{i=1}^n x_i)(\sum_{i=1}^n y_i)}{n}$

$S_{xx}=\sum_{i=1}^n x^2_i -\frac{(\sum_{i=1}^n x_i)^2}{n}$

With these we can find the sums:

$S_{xx}=\sum_{i=1}^n x^2_i -\frac{(\sum_{i=1}^n x_i)^2}{n}=278.65-\frac{32.5^2}{4}=14.5875$

$S_{xy}=\sum_{i=1}^n x_i y_i -\frac{(\sum_{i=1}^n x_i)(\sum_{i=1}^n y_i){n}}=696.9-\frac{32.5*97}{4}=-91.225$

And the slope would be:

$m=\frac{-91.225}{14.5875}=-6.254$

Nowe we can find the means for x and y like this:

$\bar x= \frac{\sum x_i}{n}=\frac{32.5}{4}=8.125$

$\bar y= \frac{\sum y_i}{n}=\frac{97}{4}=24.25$

And we can find the intercept using this:

$b=\bar y -m \bar x=24.25-(-6.254*8.125)=75.064$

So the line would be given by:

$y=-6.254 x +75.064$

Part b

For this case we need to calculate the correlation coefficient given by:

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

$r=\frac{4(696.9)-(32.5)(97)}{\sqrt{[4(278.65) -(32.5)^2][4(3009) -(97)^2]}}=-0.937$

So then the correlation coefficient would be r =-0.932

The % of variation is given by the determination coefficient given by $r^2$ and on this case $-0.932^2 =0.8687$ , so then the % of variation explained by the linear model is 86.87%.

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2 years ago

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BlackZzzverrR [31]

I think the answer is 1 1/8

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