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3 years ago

15

Vinny is interviewing for a job. He wants his take-home pay to be atleast $42,000. What is the least salary he can earn if he pa

ys 25% income tax?

1 answer:

kondor19780726 [428]3 years ago

4 0

$56,000 - 25% = $42,000

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Modern medical practice tells us not to encourage babies to become too fat. Is there a positive correlation between the weight x

Anna11 [10]

Answer:

a) Figure attached

b) $y=1.31 x +98.57$

c) The correlation coefficient would be r =0.47719

d) $y=1.31 x +98.57=1.31*21 + 98.57 =126.08$

Step-by-step explanation:

(a) Draw a scatter diagram for the data.

See the figure attached

(b) Find x, y, b, and the equation of the least-squares line. (Round your answers to three decimal places.) x =__ y =__ b =__ y =__ + __x

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

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:

$S_{xx}=\sum_{i=1}^n x^2_i -\frac{(\sum_{i=1}^n x_i)^2}{n}=6576-\frac{300^2}{14}=147.429$

$S_{xy}=\sum_{i=1}^n x_i y_i -\frac{(\sum_{i=1}^n x_i)(\sum_{i=1}^n y_i){n}}=38186-\frac{300*1773}{14}=193.143$

And the slope would be:

$m=\frac{193.143}{147.429}=1.31$

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

$\bar x= \frac{\sum x_i}{n}=\frac{300}{14}=21.429$

$\bar y= \frac{\sum y_i}{n}=\frac{1773}{14}=126.643$

And we can find the intercept using this:

$b=\bar y -m \bar x=126.643-(1.31*21.429)=98.571$

So the line would be given by:

$y=1.31 x +98.57$

(c) Find the sample correlation coefficient r and the coefficient of determination r?2. (Round your answers to three decimal places.)

n=14 $\sum x = 300, \sum y = 1773, \sum xy=38186, \sum x^2 =6576, \sum y^2 =225649$

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

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

$r=\frac{14(38186)-(300)(1773)}{\sqrt{[14(6576) -(300)^2][14(225649) -(1773)^2]}}=0.9534$

So then the correlation coefficient would be r =0.47719

What percentage of variation in y is explained by the least-squares model? (Round your answer to one decimal place.)

The % of variation is given by the determination coefficient given by $r^2$ and on this case $0.47719^2 =0.2277$ , so then the % of variation explaines is 22.8%.

(d) If a female baby weighs 21 pounds at 1 year, what do you predict she will weigh at 30 years of age? (Round your answer to two decimal places.) ___ lb

So we can replace in the linear model like this:

$y=1.31 x +98.57=1.31*21 + 98.57 =126.08$

7 0

3 years ago

4p + 1 = 10 what is the value of p?

fredd [130]

Answer:

p = 9/4 or 2.25

Step-by-step explanation:

4p + 1 = 10

-1 -1

4p = 9

Divide 4 on both sides

p = 9/4 or 2.25

5 0

3 years ago

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If f(x) = k(x - 2)^2, where k is positive, what is the effect on the graph of f(x) as k increases

pashok25 [27]

The answer is B. Lana Rhoades

4 0

3 years ago

Read 2 more answers

A mutual fund company offers its customers a variety of funds: a money-market fund, three different bond funds (short, intermedi

bagirrra123 [75]

Answer:

a. 7% probability that the selected individual owns shares in the balanced fund.

b. 31% probability that the individual owns shares in a bond fund.

c. 58% probability that the selected individual does not own shares in a stock fund

Step-by-step explanation:

a. What is the probability that the selected individual owns shares in the balanced fund?

7% of the individuals owns shares in the balanced fund, so 7% probability that the selected individual owns shares in the balanced fund.

b. What is the probability that the individual owns shares in a bond fund?

Bond funds (short, intermediate, and long-term):

15%(short-term) + 11%(intermediate-term) + 5%(long-term)

15%+11%+5% = 31%

31% probability that the individual owns shares in a bond fund.

c. What is the probability that the selected individual does not own shares in a stock fund?

Anything but moderate and high risk stock%.

The sum of all probabilities is 100%.

18% + 24% = 42% own stock fund.

100 - 42 = 58%

58% probability that the selected individual does not own shares in a stock fund

3 0

3 years ago

A random sample of the costs of repair jobs at a large muffler repair shop produces a mean of $127.95. and a standard deviation

lubasha [3.4K]

Answer:

$127.95-1.685\frac{24.03}{\sqrt{40}}=121.55$

$127.95 +1.685\frac{24.03}{\sqrt{40}}=134.35$

So on this case the 90% confidence interval would be given by (121.55;134.35)

Step-by-step explanation:

Previous concepts

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

$\bar X=127.95$ represent the sample mean for the sample

$\mu$ population mean (variable of interest)

s=24.03 represent the sample standard deviation

n represent the sample size

Solution to the problem

The confidence interval for the mean is given by the following formula:

$\bar X \pm t_{\alpha/2}\frac{s}{\sqrt{n}}$ (1)

In order to calculate the critical value $t_{\alpha/2}$ we need to find first the degrees of freedom, given by:

$df=n-1=40-1=39$

Since the Confidence is 0.90 or 90%, the value of $\alpha=0.1$ and $\alpha/2 =0.05$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-T.INV(0.05,39)".And we see that $t_{\alpha/2}=1.685$

Now we have everything in order to replace into formula (1):

$127.95-1.685\frac{24.03}{\sqrt{40}}=121.55$

$127.95 +1.685\frac{24.03}{\sqrt{40}}=134.35$

So on this case the 90% confidence interval would be given by (121.55;134.35)

8 0

3 years ago