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3 years ago

Twelve more then the product of 5 and a number x? x is 2

Mathematics

1 answer:

yaroslaw [1]3 years ago

3 0

Answer:

Step-by-step explanation:

5 * 2 = 10

10 + 12 (because 12 more)

=22

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The proprietor of a boutique in New York wanted to determine the average age of his customers. A random sample of 25 customers r

jolli1 [7]

Answer:

$28-2.064\frac{10}{\sqrt{25}}=23.872$

$28+2.064\frac{10}{\sqrt{25}}=32.128$

So on this case the 95% confidence interval would be given by (23.9;32.1)

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".

$\bar X=28$ represent the sample mean

$\mu$ population mean (variable of interest)

s=10 represent the sample standard deviation

n=25 represent the sample size

Solution to the problem

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:

$df=n-1=25-1=24$

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 table to find the critical value. The excel command would be: "=-T.INV(0.025,24)".And we see that $t_{\alpha/2}=2.064$

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

$28-2.064\frac{10}{\sqrt{25}}=23.872$

$28+2.064\frac{10}{\sqrt{25}}=32.128$

So on this case the 95% confidence interval would be given by (23.9;32.1)

7 0

3 years ago

What's 19/30 x 12/16?

mr Goodwill [35]

19/40 as a fraction and decimal it is 0.475

6 0

3 years ago

Read 2 more answers

Hi, im 13 years old, im responsible, and have a deep love for horses. Some tips on how to persuade my parents that i will be res

dimaraw [331]

Answer:

prove you are responisble and you will take ggod care of it

Step-by-step explanation:

5 0

3 years ago

Read 2 more answers

Pls answer this. its easy but for me nah

zlopas [31]

Answer:

1. acute

2. Right

3. maybe acute

4. obtuse

5. acute

6. obtuse

7. straight

8. obtuse

9. acute

10. obtuse

11. acute

12. acute

13. obtuse

14. obtuse

8 0

3 years ago

All 231 students in math club went on a field trip some rode in vans that held 7 people and some rode on buses that held 25 peop

MariettaO [177]

Answer:

8 vans

7 buses

Step-by-step explanation:

Let there be "b" buses

and "v" vans

Since 7 people is the capacity of vans, the total capacity is

Also, since 25 people is the capacity of 1 bus, the total capacity is

25b

In total 231 people, so we can write our first equation as:

7v + 25b = 231

Now, we know there are 15 vehicles (bus + vans) in total, so we can write our 2nd equation as:

v + b = 15

Now, we solve for v and b. Let's solve the 2nd equation for v and substitute that into 1st and solve for b first:

v + b = 15

v = 15 - b

Now,

$7v + 25b = 231\\7(15-b) + 25b = 231\\105-7b+25b=231\\18b=126\\b=7$

Hence, there are 7 buses

Since 15 vehicles in total, the number of vans is:

15 - 7 = 8 vans

So,

8 vans

7 buses

8 0

4 years ago