Rewrite the fraction in the sentence below as a percentage. From 125 yards away, a marksman hit 14/25 of the targets last year.

How heavy a load (pounds) is needed to pull apart pieces of wood 4 inches long and 1.5 inches square? Here are data from student

statuscvo [17]

Answer:

a. (29526.192 , 32155.808)

b. (29673.9301 , 32008.0699)

Step-by-step explanation:

on calculation, we find that sample mean = 30843 and sample standard deviation = 3018.504, and n=20

1)

Sample Mean = 30841

SD = 3000

Sample Size (n) = 20

Standard Error (SE) = SD/root(n) = 670.8204

alpha (a) = 1 - 0.95 = 0.05

z critical value for 95% confidence interval:

z(a/2) = z(0.025) = 1.96

Margin of Error (ME) = z(a/2) x SE = 1314.808

95% confidence interval is given by:

Sample Mean +/- (Margin of Error) = 30841 +/- 1314.808

= (29526.192 , 32155.808)

2)when std dev of population is not known, we use sample's, but we have to use t instead of z

Sample Mean = 30841

SD = 3018.504

Sample Size (n) = 20

Standard Error (SE) = SD/root(n) = 674.958

alpha (a) = 1-0.9 = 0.1

we use t-distribution as population standard deviation is unknown

t(a/2, n-1 ) = 1.7291

Margin of Error (ME) = t(a/2,n-1)x SE = 1167.0699

90% confidence interval is given by:

Sample Mean +/- (Margin of Error)

30841 +/- 1167.0699 = (29673.9301 , 32008.0699)

4 0

3 years ago

A set of n = 15 pairs of X and Y scores has SSX = 10, SSY = 40, and SP = 30. What is the slope for the regression equation for p

Mumz [18]

Answer:

3

Step-by-step explanation:

We have given $SS_X=10$ , $SS_Y=40$ and SP =30

We have to find the slope for regression on Y from X

The slope on Y from X is given by $b_{yx}=\frac{SP}{SS_X}$

As we have given the value of SP =30 and value of $SS_X=10$

So slope for regression will be $b_{yx}=\frac{30}{10}=3$

3 0

3 years ago

Evaluate the integral Integral ∫ from (1,2,3 ) to (5, 7,-2 ) y dx + x dy + 4 dz by finding parametric equations for the line seg

n200080 [17]

$\vec F(x,y,z)=y\,\vec\imath+x\,\vec\jmath+3\,\vec k$

is conservative if there is a scalar function $f(x,y,z)$ such that $\nabla f=\vec F$ . This would require

$\dfrac{\partial f}{\partial x}=y$

$\dfrac{\partial f}{\partial y}=x$

$\dfrac{\partial f}{\partial z}=3$

(or perhaps the last partial derivative should be 4 to match up with the integral?)

From these equations we find

$f(x,y,z)=xy+g(y,z)$

$\dfrac{\partial f}{\partial y}=x=x+\dfrac{\partial g}{\partial y}\implies\dfrac{\partial g}{\partial y}=0\implies g(y,z)=h(z)$

$f(x,y,z)=xy+h(z)$

$\dfrac{\partial f}{\partial z}=3=\dfrac{\mathrm dh}{\mathrm dz}\implies h(z)=3z+C$

$f(x,y,z)=xy+3z+C$

so $\vec F$ is indeed conservative, and the gradient theorem (a.k.a. fundamental theorem of calculus for line integrals) applies. The value of the line integral depends only the endpoints:

$\displaystyle\int_{(1,2,3)}^{(5,7,-2)}y\,\mathrm dx+x\,\mathrm dy+3\,\mathrm dz=\int_{(1,2,3)}^{(5,7,-2)}\nabla f(x,y,z)\cdot\mathrm d\vec r$

$=f(5,7,-2)-f(1,2,3)=\boxed{18}$

8 0

2 years ago

Which choice is equivalent to the expression below? HELP PLEASE THE PROBLEM IS ON THE PICTURE!!!!!!!

zvonat [6]

The correct answer is C

5 0

3 years ago

397 of 514 randomly selected U.S. adults interviewed said they would not be bothered if the National Security Agency collected r

Afina-wow [57]

Answer:

z=14.73

p=0.000

for 99% confidence level the null hypothesis is rejected, thus majority of us adults would not bothered if the NSA collected personal records.

Step-by-step explanation:

$H_{0}$ : Half of US adults would not bothered if the NSA collect records of personal telephone calls

$H_{A}$ : Majority of the adults would not bothered if the NSA collect records of personal telephone calls

According to the sample, z-value can be found using the formula:

z= $\frac{X-M}{\sqrt{n*p*(1-p)} }$ where

X is the adults, who would not be bothered in the survey (397)
M is the mean of the distribution of null hypothesis (257)
n is the sample size (514)
p is the proportion of the sample, who said they would not bothered ( $\frac{397}{514}$ ≈ 0.77)

Putting these numbers in the formula,

z=14.73 and corresponding p value is p≈0.000

Since p<0.01, for 99% confidence level we reject the null hypothesis, thus majority of us adults would not bothered if the NSA collected personal records.

8 0

3 years ago