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
mel-nik [20]
3 years ago
8

The principal randomly selected six students to take an aptitude test. their scores were: 81.4 78.6 71.3 77.8 76.9 77.7 determin

e a 90% confidence interval for the mean score for all students.
Mathematics
1 answer:
Firdavs [7]3 years ago
3 0
The confidence interval is 77.28\pm 2.23.

We first find the mean.  Add together all of the data points and divide by 6, the number of data points; the mean is 77.28.

Next we find the standard deviation.  Find the difference between each data point and the mean; square it; find the sum; divide by the number of data points; take the square root.  The standard deviation is 3.32.

To find the margin of error, we calculate the z-score associated with this level of confidence.  100-90 = 10% = 0.1; 0.1/2 = 0.05; 1-0.05 = 0.95.  Using a z-table (http://www.z-table.com) we see that this is between two scores, 1.64 and 1.65; we will use 1.645.

The margin of error is given by
z * (σ/√n) = 1.645*(3.32/√6) = 2.23.

Thus the confidence interval is 77.28 +/ 2.23.
You might be interested in
A bouncy ball is dropped from a height of 16ft and always rebounds of the distance of the previous fall.
nika2105 [10]
16x5=80 cause if it bounces 16 times 5 times then
4 0
2 years ago
Read 2 more answers
Witch method will NOT get you to the point (1.5, 4)?
Bad White [126]
Left down, or “Starting at the origin, go 4 spaces to the right and then 1and1/2 spaces up.” This would bring you to the point (4,1and1/2)
8 0
2 years ago
How to add it because I don not know how to do it
koban [17]
   1              3            4
1 --    +    1 --   =    2 --
   5              5            5

Explanation:

1 + 1 = 2
1/5 + 3/5 = 4/5<span />
7 0
3 years ago
Read 2 more answers
Help me please!!!!!!!?
vovikov84 [41]
It is c.it is actually 1.548 but you round it so....
5 0
3 years ago
Read 2 more answers
The difference of two numbers is 15. Five times the smaller is the same as 9 less than twice the larger. Find the numbers
Usimov [2.4K]

Answer:

x= -13

y= -28

Step-by-step explanation:

To find the two numbers, write a system of equations with x as one number and y as another:

x-y=15

5x=2y-9

Use substitution to substitute one equation into another. Then solve for the variable.

x=15+y into 5x=2y-9

becomes

5(15+y) = 2y-9

75+5y = 2y- 9

75+3y= -9

3y = -84

y= -28

To find x, substitute y= -28 into one equation.

x - (-28) = 15

x+28 =15

x = 15-28

x=-13




6 0
3 years ago
Other questions:
  • PLEASE HELP ASAPPPPPPPPPPP
    12·1 answer
  • 10 = 4 + c Question 1 options: c = 2 c = 6 c = 12 c = 14
    8·2 answers
  • Triangles A C B and M Q R are shown. Sides A B and M R are congruent. Angles C A B and M R Q are 42 degrees. Angle C B A is 53 d
    7·2 answers
  • 1 millimeter on the map represents 1 meter on the ground. What is the ratio
    7·1 answer
  • Find the volume of the composite figure. Round to the nearest tenth. The base of each pyramid is a square with a side length of
    6·1 answer
  • Lin can read at rate of 20 pages in 35 minutes she just borrowed a book from library that 48 pages how many minutes will it take
    13·1 answer
  • (2x+2)(2x+2)-10=90<br><br> Please help me with the homework, I give ten points to the best answer
    10·2 answers
  • Please help with this ...thanks
    13·2 answers
  • It is a solid shape that contains lateral surface and two circular bases which are parallel and congruent.
    15·1 answer
  • Please help me bef9yer9h
    14·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!