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2 years ago

How many terms are in expression 9+14d+5w+7

Mathematics

1 answer:

tamaranim1 [39]2 years ago

4 0

9514 1404 393

Answer:

Step-by-step explanation:

The terms are separated by addition/subtraction symbols. There are 4 terms.

With parentheses around each term, you have ...

(9) + (14d) + (5w) + (7) . . . . 4 terms

_____

The two constant terms can be combined to give an expression with 3 terms:

14d +5w +16

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A university planner wants to determine the proportion of spring semester students who will attend summer school. Suppose the un

ss7ja [257]

Answer:

$n=\frac{\hat p (1-\hat p)}{(\frac{ME}{z})^2}$ (b)

Since we don't have prior estimation for the population proportion we can use the value $\hat p =0.5$ . And replacing into equation (b) the values from part a we got:

$n=\frac{0.5(1-0.5)}{(\frac{0.112}{1.64})^2}=53.60$

And rounded up we have that n=54

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".

Solution to the problem

In order to find the critical value we need to take in count that we are finding the interval for a proportion, so on this case we need to use the z distribution. Since our interval is at 90% of confidence, our significance level would be given by $\alpha=1-0.90=0.1$ and $\alpha/2 =0.005$ . And the critical value would be given by:

$z_{\alpha/2}=-1.64, z_{1-\alpha/2}=1.64$

The margin of error for the proportion interval is given by this formula:

$ME=z_{\alpha/2}\sqrt{\frac{\hat p (1-\hat p)}{n}}$ (a)

And on this case we have that $ME =\pm 0.112$ and we are interested in order to find the value of n, if we solve n from equation (a) we got:

$n=\frac{\hat p (1-\hat p)}{(\frac{ME}{z})^2}$ (b)

Since we don't have prior estimation for the population proportion we can use the value $\hat p =0.5$ . And replacing into equation (b) the values from part a we got:

$n=\frac{0.5(1-0.5)}{(\frac{0.112}{1.64})^2}=53.60$

And rounded up we have that n=54

3 0

2 years ago

The level of dissolved oxygen (DO) in a stream or river is an important indicator of the water's ability to support aquatic life

kaheart [24]

Answer:

a) It is most appropiate to apply t procedures with this sample because the population standard deviation is unknown. We have to estimate it from the sample standard deviation.

b) There is no enough evidence to claim that disolved oxygen level is below 5 mg/l.

c) As the null hypothesis was not rejected, the only error we could have made is a Type II error.

This Type II error is made when fail to reject the null hypotesis even when the alternative hypothesis is true.

In this context, it would mean that the aquatic life is really at risk (dissolved oxygen levels below 5 mg/l), but because the sample results combined with its size were not giving enough evidence to prove the claim.

Step-by-step explanation:

b) We have to perform a hypothesis test on the mean, at a significance level of 0.05.

The null and alternative hypothesis are:

$H_0:\mu\geq 5\\\\H_a: \mu$

The sample mean is 4.77 and the sample standard deviation is 0.94.

The sample size is 15, so the degrees of freedom are:

$df=n-1=15-1=14$

The t-statistic is:

$t=\frac{\bar x-\mu}{s/\sqrt{n}} =\frac{4.77-5}{0.94/\sqrt{15}}= \frac{-0.23}{0.242}=-0.95$

For a t=0.95 and df=14, the P-value is P=0.18.

This P-value is bigger than the significance level, so the null hypothesis is failed to be rejected.

There is no enough evidence to claim that disolved oxygen level is below 5 mg/l.

6 0

2 years ago

2 x 3.6 find the product

Rus_ich [418]

Answer:

7.2

Step-by-step explanation:

5 0

2 years ago

Read 2 more answers

The table can be used to determine the solution of equations, 2x - 2y = 6 and 4x + 4y = 28.

NeTakaya

Answer:

(5, 2)

Step-by-step explanation:

Given the following system of equations;

2x - 2y = 6 ......equation 1.

4x + 4y = 28 ......equation 2.

To get an equivalent equation, we would multiply eqn 1 by 2;

2 * (2x - 2y = 6) = 4x - 4y = 12

The new equivalent system of equations are;

4x - 4y = 12

4x + 4y = 28

Adding the equivalent system of equations, we have;

(4x + 4x) + (-4y + 4y) = (12 + 28)

8x + 0 = 40

8x = 40

x = 40/8

x = 5

Next, we would find the value of y;

2x - 2y = 6

Substituting the value of x, we have;

2(5) - 2y = 6

10 - 2y = 6

Rearranging the equation (collecting like terms), we have;

2y = 10 - 6

2y = 4

y = 4/2

y = 2

Therefore, the solutions to the new system of equations are 5 and 2.

Check:

2x - 2y = 6

Substituting the values, we have;

2(5) - 2(2) = 6

10 - 4 = 6

6 = 6

3 0

2 years ago

Let f(x) be the elevation in feet of the mississippi river x miles from its source. what are the units of f '(x)?

MAVERICK [17]

Forgot
Remember
X+6=3 wat i donnu

5 0

2 years ago