A teacher records the test scores of several students. Find the median (middle) score. 80, 72, 76, 71, 75, 78, 72, 74, 82,70

(1 point) Suppose we want a 95% confidence interval for the average amount spent on books by freshmen in their first year at col

Ne4ueva [31]

Answer:

a) $n=(\frac{1.960(16)}{5})^2 =39.33 \approx 40$

So the answer for this case would be n=40 rounded up to the nearest integer

b) For this case if we see the formula for the margin of error

$ME=z_{\alpha/2}\frac{s}{\sqrt{n}}$ (a)

We can see that the margin of error is inversely proportional to the sample size so if we want a samller margin of error we need a LARGER sample

Answer: LARGER

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".

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

$\mu$ population mean

$\sigma=16$ represent the population standard deviation

n represent the sample size

Solution to the problem

Part a

The margin of error is given by this formula:

$ME=z_{\alpha/2}\frac{s}{\sqrt{n}}$ (a)

And on this case we have that ME =5 and we are interested in order to find the value of n, if we solve n from equation (a) we got:

$n=(\frac{z_{\alpha/2} \sigma}{ME})^2$ (b)

The critical value for 95% of confidence interval now can be founded using the normal distribution. And in excel we can use this formla to find it:"=-NORM.INV(0.025;0;1)", and we got $z_{\alpha/2}=1.960$ , replacing into formula (b) we got:

$n=(\frac{1.960(16)}{5})^2 =39.33 \approx 40$

So the answer for this case would be n=40 rounded up to the nearest integer

Part b

For this case if we see the formula for the margin of error

$ME=z_{\alpha/2}\frac{s}{\sqrt{n}}$ (a)

We can see that the margin of error is inversely proportional to the sample size so if we want a samller margin of error we need a LARGER sample

Answer: LARGER

5 0

3 years ago

Shelly is making an apple pie. She needs 1/2 of a cup of sugar for her pie . How many cups of sugar will she need if she need if

sergejj [24]

Answer: Shelly will need 6 cups of sugar.

Step-by-step explanation:

Multiply 3 by 1/2

6 0

3 years ago

Read 2 more answers

The length of a rectangle is 3 inches more than its width. the area of the rectangle is 40 square inches. what is the length, in

IceJOKER [234]

Since width is the smaller value, set width=x. That wold mean that length=x+3. Since Area=width*length, 40=x(3+x). Distribute the x to give you 40=3x+x^2. Set the equation equal to 0 giving you x^2+3x-40=0. Factor the equation to give you (x+8)(x-5)=0. Set each factor equal to 0. x+8=0 gives you x=-8 & x=-5 gives you x=5. Since we're working with lengths of objects, it can't be negative. Therefore, your width is 5. To find length, substitute width into the original expression (x+3). Therefore, length is 5+3=8.

4 0

3 years ago

What is the converse of the conditional statement?

dem82 [27]

Answer:

according to me 1st option seems to be correct❤️

5 0

3 years ago

Subtract this please

cupoosta [38]

Answer:

B. 3x^2 - 13x + 7

Step-by-step explanation:

6x^2 - 5x + 3 - (3x^2 + 8x - 4)

6x^2 - 5x + 3 - 3x^2 - 8x + 4

3x^2 - 13x + 7

4 0

3 years ago

Read 2 more answers