1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Leya [2.2K]
3 years ago
12

A student wanted to construct a 95% confidence interval for the average age of students in her statistics class. She randomly se

lected 9 students. Their average age was 19.1 years with a standard deviation of 1.5 years. What is the 99% confidence interval for the population mean?
Mathematics
1 answer:
Darina [25.2K]3 years ago
7 0

Answer: (17.42, 20.78)

Step-by-step explanation:

As per given , we have

Sample size : n= 9

\overline{x}=19.1 years

Population standard deviation is not given , so it follows t-distribution.

Sample standard deviation : s= 1.5 years

Confidence level : 99% or 0.99

Significance level : \alpha= 1-0.99=0.01

Degree of freedom : df= 8  (∵df =n-1)

Critical value : t_c=t_{(\alpha/2,\ df)}=t_{0.005,\ 8}= 3.355

The 99% confidence interval for the population mean would be :-

\overline{x}\pm t_c\dfrac{s}{\sqrt{n}}

19.1\pm (3.355)\dfrac{1.5}{\sqrt{ 9}}\\\\=19.1\pm1.6775\\\\=(19.1-1.6775,\ 19.1+1.6775)\\\\=(17.4225,\ 20.7775)\approx(17.42,\ 20.78)

Hence, the 99% confidence interval for the population mean is (17.42, 20.78) .

You might be interested in
The population of West Algebra can be modeled by the equation
AleksAgata [21]

Answer:

65.7

Step-by-step explanation:

Given the population of West Algebra can be modeled by the equation

P = 30. 1.04^T

If T is the number of years since 2000 and P is  the population in millions, in 2020, T = 2020 - 2000 = 20

Substitute T = 20 into the expression and get T

P = 30. 1.04^20

P = 30(2.1911)

P = 65.73

Hence the amount of people that will be there in 2020 is 65.7million people

6 0
3 years ago
Brainliest pls help
Airida [17]
<h3>Volume:</h3>

With this prism, first separate it into a rectangular prism and a right triangle prism.

First, with the rectangular prism, it would have the units 5 * 5 * 6.3. Then with the right triangle prism, it would take the rest of the remaining space of it, being 3 * 5 * 6.3

The equation for the volume of a rectangular prism is L*W*H and the equation for the volume of a right triangle prism is (L*W*H) / 2.

With this, plug the numbers in for both prisms to get the volume of each of them:

<u>Rectangular prism Volume</u>

5*5*6.3

<em>157.5</em>

<u>Right triangle prism Volume</u>

(3*5*6.3) / 2

94.5 / 2

<em>47.25</em>

Lastly, combine these two values to get the total volume:

157.5 + 47.25 = 204.75 (Round Up) -->

<em><u>204.8 cm^3 = Total Volume </u></em>

<h3>Surface Area:</h3>

Next, with the surface area of the prism. For this, lets combine all of the faces of the prism then add them all up.

First, lets do the bottom of the prism, or the base. It uses the lengths 8 cm and 6.3 cm. Lets do L * W to get the area of this face:

8 * 6.3 = 50.4

Next, lets do the slant side of it, which has the lengths 5.8 and 6.3.

5.8 * 6.3 = 36.54

Then, the top side with the lengths 5cm and 6.3 cm.

5.3 * 6.3 = 33.39

After that, the left side face that opposite to the slantly one:

5 * 6.3 = 31.5

Saving the most tedious part of it for last, the right trapezoids. Luckily, there is an equation for this:

<em>1/2 x (Sum of parallel sides) x (perpendicular distance between the parallel sides).</em>

<em>So, within each of these right </em>trapezoids, there's the parallel sides of 5 and 8. There's also a perpendicular side of 5cm. With this, we can plug this into the equation to solve for this part:

1/2 x (5+8) * (5)

1/2 x (13) * (5)

1/2 x (65)

32.5

Since there's two of them, times this by 2:

32.5 * 2 ---> 65.

Now, with the area of all of the faces, these can be added up for the total surface area:

50.4 + 36.54 + 33.39 + 31.5 + 65 ---> 216.83 (Round Down)-->

<u><em>216.8 cm^2 = Total Surface Area</em></u>

<em />

8 0
3 years ago
Una caja en forma de prisma rectangular tiene 10cm3 de volumen.Si la longitud de cada arista se multiplica por 4, ¿cual sera el
Salsk061 [2.6K]
40cm. Por que 10 e 4
4 0
3 years ago
X/5 + 1 = 10<br><br> It’s number 11
shusha [124]

Answer:

X = 45

Step-by-step explanation:

7 0
3 years ago
this stem and leaf plot shows the number of text messages 10 people sent yesterday. whatis the total number of text messages the
Rudiy27
To find the total number of text messages sent, you will use the stem-n-leaf plot to create a data set of all the numbers of texts sent.

To read a stem-n-leaf plot you will use the number on the left as the tens place and each number to the right of it creates a new number in the data set.
 
See the key for help!

Here is the list of the all the data:

0, 0, 7, 9, 10, 10, 15, 20, 23, 32

To find the total number of text messages sent, add these together.

The answer is 126 text messages.


3 0
3 years ago
Other questions:
  • The original price af a shirt is $120, the percent of decimal is %80 what is that sale price?
    9·1 answer
  • Expression: 6(m + 2 + 7m)
    15·1 answer
  • Solve each inequality of -4x -2&lt;8
    8·1 answer
  • Find four rational number between 1/4 and 2/3.
    14·1 answer
  • If y= 3x + 6, what is the minimum value of (x^3)(y)?
    13·1 answer
  • Solve for x.<br><br> <img src="https://tex.z-dn.net/?f=15log_%7B8%7D%20%28-2x-7%29-2%3D3" id="TexFormula1" title="15log_{8} (-2x
    5·1 answer
  • Each employee in a company is either right-handed or left-handed.
    11·1 answer
  • What’s the total badges and buy all the Boy Scouts<br> 26<br> 25<br> 52<br> 78
    13·1 answer
  • 100 POINTS!
    6·1 answer
  • What is the area of this figure?<br><br> Enter your answer in the box.
    5·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!