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3 years ago

Budgeting and being a smart consumer

Mathematics

1 answer:

Leni [432]3 years ago

6 0

Answer:

please explain what I really need to answer

Step-by-step explanation:

it will be my pleasure to help you

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Here are summary statistics for randomly selected weights of newborn girls: nequals=174174, x overbarxequals=30.930.9 hg, seq

MaRussiya [10]

Answer:

The 95% confidence interval would be given by (29.780;32.020)

Step-by-step explanation:

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".

$\bar X=30.9$ represent the sample mean for the sample

$\mu$ population mean (variable of interest)

s=7.5 represent the sample standard deviation

n=174 represent the sample size

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

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

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

$df=n-1=174-1=173$

Since the Confidence is 0.95 or 95%, the value of $\alpha=0.05$ and $\alpha/2 =0.025$ , and we can use excel, a calculator or a tabel to find the critical value. The excel command would be: "=-T.INV(0.025,173)".And we see that $t_{\alpha/2}=1.97$ , this value is similar to the obtained with the normal standard distribution since the sample size is large to approximate the t distribution with the normal distribution.

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

$30.9-1.97\frac{7.5}{\sqrt{174}}=29.780$

$30.9+1.97\frac{7.5}{\sqrt{174}}=32.020$

So on this case the 95% confidence interval would be given by (29.780;32.020)

The value 29.6 is not contained on the interval calculated.

5 0

3 years ago

Shop sells bagles for 5 per dozen how much bagles can you buy for 50

spayn [35]

120 Bagels
Explanation:
if you get 12 bagels for 5 dollars, and your wondering how many you’d get for 50 dollars, 5 times 10 is 50 and 10 times 12 is 120. That doesn’t make the most sense but yes

3 0

3 years ago

If b/a=2/5, what is the value of 2 (a/b)

Nina [5.8K]

$\dfrac{b}{a}=\dfrac{2}{5}\to\dfrac{a}{b}=\dfrac{5}{2}\ \ \ |\cdot2\\\\2\left(\dfrac{a}{b}\right)=2\cdot\dfrac{5}{2}\\\\2\left(\dfrac{a}{b}\right)=5$

Answer: 2(a/b) = 5

3 0

3 years ago

If A = (-2, -4) and B = (-8, 4), what is the length of AB?

svetoff [14.1K]

Answer: OPTION D

Step-by-step explanation:

To solve this exercise you must use the formula for calculate the distance between two points, which is shown below:

$d_{(A,B)}=\sqrt{(x_2-x_1)^2+(y_2-y_1)^2}$

Now, you must substitute the points given in the problem into the formula:

A(-2,-4)

B(-8,4)

$d_{(A,B)}=\sqrt{(-8-(-2))^2+(4-(-4))^2}$

Then, the result is:

$d_{(A,B)}=10units$

5 0

3 years ago

Read 2 more answers

PLEASE MAKE SURE HELP ME!

bulgar [2K]

Answer:

1. The first problem is wrong, it should be 0.5(3(15) + 2(20)) because the parentheses make sure that every purchased item is being divided by 2 (multiplying by 0.5 is the same as dividing by 2)

2. The second problem is partially correct. The first two answers you have checked are correct, but the last one is wrong. The third answer should be 6 + 12 instead because that's just a simplified version of 2(3) + 6(2), meaning they are equal

3. I cannot read your answers in the "Why or Why Not" column in the third problem, but the answers you gave in the "Evaluate" and "Does It Work?" columns are all correct.

7 0

3 years ago