Select the inequality below that could have 7 as a solution.

A doctor at a local hospital is interested in estimating the birth weight of infants. How large a sample must she select if she

Nataly_w [17]

Answer:

The minimum sample size needed is $n = (\frac{1.96\sqrt{\sigma}}{4})^2$ . If n is a decimal number, it is rounded up to the next integer. $\sigma$ is the standard deviation of the population.

Step-by-step explanation:

We have that to find our $\alpha$ level, that is the subtraction of 1 by the confidence interval divided by 2. So:

$\alpha = \frac{1 - 0.9}{2} = 0.05$

Now, we have to find z in the Z-table as such z has a p-value of $1 - \alpha$ .

That is z with a pvalue of $1 - 0.05 = 0.95$ , so Z = 1.645.

Now, find the margin of error M as such

$M = z\frac{\sigma}{\sqrt{n}}$

In which $\sigma$ is the standard deviation of the population and n is the size of the sample.

How large a sample must she select if she desires to be 90% confident that her estimate is within 4 ounces of the true mean?

A sample of n is needed, and n is found when M = 4. So

$M = z\frac{\sigma}{\sqrt{n}}$

$4 = 1.96\frac{\sigma}{\sqrt{n}}$

$4\sqrt{n} = 1.96\sqrt{\sigma}$

$\sqrt{n} = \frac{1.96\sqrt{\sigma}}{4}$

$(\sqrt{n})^2 = (\frac{1.96\sqrt{\sigma}}{4})^2$

$n = (\frac{1.96\sqrt{\sigma}}{4})^2$

The minimum sample size needed is $n = (\frac{1.96\sqrt{\sigma}}{4})^2$ . If n is a decimal number, it is rounded up to the next integer. $\sigma$ is the standard deviation of the population.

4 0

3 years ago

15 points What is the equation of the graph below?

aleksandrvk [35]

We need to see all the given answers

8 0

3 years ago

A force of 60 N is used to stretch two springs that are initially the same length. Spring A has a spring constant of 4 N/m, and

goblinko [34]

Answer:

D:Spring A is 3 m longer than spring B because 15 – 12 = 3.

Step-by-step explanation:

In this question, you should remember the Hooke's Law in physics.

The Hooke's Law simply explains that the extension that occurs on a spring is directly proportional to the load applied on it.

The mathematical expression for this law is

$F=-kx$

where;

F= force applied on the spring

x = the extension on the spring

k= the spring constant which varies in spring.

The question will need you to calculate the extension on the springs A and B then compare the values obtained.

In spring A

Force, F=60N and spring constant ,k=4 N/m

To find the extension x apply the expression;

$F=-kx\\\\60=-4*x\\\\60=-4x\\\\\frac{60}{-4} =\frac{-4x}{-4} \\\\\\-15=x$

Here the spring extension is 15 m

In spring B

Force, F=60N and spring constant , k=5N/m

To find the extension x apply the same expression

$F=-kx\\\\60=-5*x\\\\60=-5x\\\\\\\frac{60}{-5} =\frac{-5x}{-5} \\\\\\-12=x$

Here the extension on the spring is 12 m

Compare

The extension on spring A is 3 m longer than that in spring B because when you subtract the value of spring B from that in spring A you get 3m

$=15m-12m=3m$

5 0

3 years ago

Part A: Find a rational number that is between 5.2 and 5.5. Explain why it is rational. (2 points) Part B: Find an irrational nu

max2010maxim [7]

A rational number can always be represented as a fraction.
5.2 = 52/10
5.5 = 55/10

A number between them would be 54/10 since 54 is between 52 and 55.

An irrational number cannot be represented as a fraction. A good example of an irrational number is the square root of a number.
sqrt(5.2^2) = 5.2 ----> 5.2^2 = 27.04
sqrt(5.5^2) = 5.5 ----> 5.5^2 = 30.25

The square root of a number between 27.04 and 30.25 will be an irrational number between 5.2 and 5.5
sqrt(28) = 5.2915...

3 0

3 years ago

Solve the equation (If possible please show work)

deff fn [24]

Answer:

$x=-3$