What is 15% of 144,000

What is the value of w in the equation 3/4w+8=1/3w-7

zhuklara [117]

3/4w+8=1/3w-7
w=36
refer to the picture above

5 0

3 years ago

The mean weight of 10 randomly selected newborn babies at a local hospital is 7.14 lbs and the standard deviation is 0.87 lbs. A

sergejj [24]

Answer:

a) $ME= 1.83 \frac{0.87}{\sqrt{10}}=0.5035$

b) 90% of all samples of size 10 have sample means within 0.5035 of the population mean.

c) The 90% confidence interval would be given by (6.636;7.643)

d) Yes, since the lower limit for the 90% confidence interval is higher than the value of 6.5 we can conclude that the true mean is significantly higher than 6.5 at 10% of significance. (6.636>6.5)

e) If we increase the confidence level that implies increase the margin of error. Since with more confidence level the value for the critical value $t_{\alpha/2}$ increase. So then the new interval would be wider than the original.

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".

$\bar X=7.14$ represent the sample mean for the sample

$\mu$ population mean (variable of interest)

s=0.87 represent the sample standard deviation

n=10 represent the sample size

Part a

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

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

And the margin of error is given by:

$ME= t_{\alpha/2}\frac{s}{\sqrt{n}}$

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

$df=n-1=10-1=9$

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(0.05,9)".And we see that $t_{\alpha/2}=1.83$

$ME= 1.83 \frac{0.87}{\sqrt{10}}=0.5035$

Part b

90% of all samples of size 10 have sample means within 0.5035 of the population mean.

Part c

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

$7.14-1.83\frac{0.87}{\sqrt{10}}=6.637$

$7.14+1.83\frac{0.87}{\sqrt{10}}=7.643$

So on this case the 90% confidence interval would be given by (6.636;7.643)

Part d

Yes, since the lower limit for the 90% confidence interval is higher than the value of 6.5 we can conclude that the true mean is significantly higher than 6.5 at 10% of significance. (6.636>6.5)

Part e

If we increase the confidence level that implies increase the margin of error. Since with more confidence level the value for the critical value $t_{\alpha/2}$ increase. So then the new interval would be wider than the original.

7 0

4 years ago

Dividing polynomials simplify 10c+6÷2

Allushta [10]

Answer:Final result :

5c + 3

Step-by-step explanation:Step by step solution :

Step 1 :

10c + 6

Simplify ———————

2

Step 2 :

Pulling out like terms :

2.1 Pull out like factors :

10c + 6 = 2 • (5c + 3)

Final result :

5c + 3

5 0

3 years ago

A regression was run to determine if there is a relationship between the happiness index (y) and life expectancy in years of a g

Natasha2012 [34]

Answer:

(A) $y=-0.762+0.119x$

(B) If a country increases its life expectancy, the happiness index will increase.

(C) If the life expectancy is increased by 3.5 years in a certain country, the happiness index will increase by 0.4165.

(D) If the life expectancy is 67 years in a certain country, the happiness index will be 7.21.

Step-by-step explanation:

A regression analysis was performed to determine if there is a relationship between the happiness index (y) and life expectancy in years of a given country (x).

The output of the regression analysis are as follows:

a = -0.762

b = 0.119

r² = 0.8649

r = 0.93

(A)

The equation of the Least Squares Regression line of the form y = _ + _ x is:

$y=-0.762+0.119x$

(B)

The correction between the variables happiness index (y) and life expectancy in years of a given country (x) is, 0.93.

The correlation coefficient is positive. This implies that there is a positive relation between the two variables, i.e. as the value of life expectancy in years increases the happiness index also increases.

Thus, if a country increases its life expectancy, the happiness index will increase.

(C)

Compute the value of y for x = x + 3.5 as follows:

$y=-0.762+0.119x$

$=-0.762+0.119\times (x+3.5)\\\\=(-0.762+0.119x)+0.4165\\\\=y+0.4165$

Thus, if the life expectancy is increased by 3.5 years in a certain country, the happiness index will increase by 0.4165.

(D)

Compute the value of y for x = 67 as follows:

$y=-0.762+0.119x$

$=-0.762+0.119\times 67\\\\=-0.762+7.973\\\\=7.211\\\\\approx 7.21$

Thus, if the life expectancy is 67 years in a certain country, the happiness index will be 7.21.

6 0

4 years ago

Write a unit rate for the situation.<br><br> 270 miles in 6 hours

poizon [28]

Answer:

45 miles per hour. 270 divided by 6 is 45 there.

Step-by-step explanation:

8 0

3 years ago