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
weqwewe [10]
2 years ago
13

Assume the population has a normal distribution. A sample of 25 randomly selected students Has a mean test score of 81.5 With a

standard deviation of 10.2. Construct a 90% confidence interval for the mean test score.
Mathematics
1 answer:
Natasha_Volkova [10]2 years ago
6 0

Answer:

The 90% confidence interval for the mean test score is between 77.29 and 85.71.

Step-by-step explanation:

We have the standard deviation for the sample, so we use the t-distribution to solve this question.

The first step to solve this problem is finding how many degrees of freedom, we have. This is the sample size subtracted by 1. So

df = 25 - 1 = 24

90% confidence interval

Now, we have to find a value of T, which is found looking at the t table, with 24 degrees of freedom(y-axis) and a confidence level of 1 - \frac{1 - 0.9}{2} = 0.95. So we have T = 2.064

The margin of error is:

M = T\frac{s}{\sqrt{n}} = 2.064\frac{10.2}{\sqrt{25}} = 4.21

In which s is the standard deviation of the sample and n is the size of the sample.

The lower end of the interval is the sample mean subtracted by M. So it is 81.5 - 4.21 = 77.29

The upper end of the interval is the sample mean added to M. So it is 81.5 + 4.21 = 85.71.

The 90% confidence interval for the mean test score is between 77.29 and 85.71.

You might be interested in
A class has 24 students. The teacher asks how many students in the class have pets and finds 5/8of the students have pets. Write
katen-ka-za [31]
24 × 5/8 = 15, you can cross multiply by doing x/24 = 5/8 And solve for x
5 0
3 years ago
Please Help me !!Q 1,2,3
Virty [35]
The area of a parallelogram is the product of the length of the base and the height measured perpendicular to the base.

1i) (20 cm)*(12 cm) = 240 cm^2

2ii) (7 cm)*(7.5 cm) = 52.5 cm^2

3iii) 27 cm^2 = (6 cm)*h
.. h = (27 cm^2)/(6 cm) = 4.5 cm
4 0
3 years ago
PLEASE HELP WILL MARK BRAINLIEST THANK YOU
Juliette [100K]

Answer:

Hope this helps u pls mark me brainlist

formula : l x B = 10 x 16 = 160 sq

6 0
2 years ago
Is compound interest always greater than simple interest ?Give examples
g100num [7]
Yes compund interest is always greater than simple interest 

simple interest = principal

compound interest = principal + accumulated interest
3 0
3 years ago
Plz helppp me right now
____ [38]

Answer:

c.

Step-by-step explanation:Because it's c.

6 0
3 years ago
Read 2 more answers
Other questions:
  • In Mr Tarkiainens each student chooses two of the topics listed in the chart above for their papers how many different pairs can
    6·1 answer
  • Choose the correct simplification of (5x3 − 5x − 8) + (2x3 + 4x + 2).
    13·2 answers
  • 30 PTS, Need assistance!
    5·2 answers
  • Name the rational numbers that are not integers from the list
    9·1 answer
  • a cone with volume 5000m^3 is dialated by a scale factor of 1/5. what is the volume of the resulting cone?​
    7·2 answers
  • Which of the following numbers is the 8th term of sequence
    13·1 answer
  • A test has twenty questions worth 100 points. The test consists of True/False questions worth 3 points each and multiple choice
    7·1 answer
  • The ratio of boys to girls in a local choir is 7:10. If there are 35 boys in the choir, how many girls are there?
    5·1 answer
  • {y=3/4x 5/2x+2y=5 need help
    10·1 answer
  • Please help quickly, it would be really appreciated.
    7·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!