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
garik1379 [7]
3 years ago
10

In a sample of 8 high school students, they spent an average of 28.8 hours each week doing sports with a sample standard deviati

on of 3.2 hours. Find the 95% confidence interval, assuming the times are normally distributed.

Mathematics
1 answer:
Alja [10]3 years ago
4 0

Answer:

26.12\:

Step-by-step explanation:

Since the population standard deviation \sigma is unknown, and the sample standard deviation s, must replace it, the t distribution  must be used for the confidence interval.

The sample size is n=8.

The degree of freedom is df=n-1, \implies df=8-1=7.

With 95% confidence level, the \alpha-level(significance level) is 5%.

Hence with 7 degrees of freedom, t_{\frac{\alpha}{2} }=2.365. (Read from the t-distribution table see attachment)

The 95% confidence interval can be found by using the formula:

\bar X-t_{\frac{\alpha}{2}}(\frac{s}{\sqrt{n} } )\:.

The sample mean is \bar X=28.8 hours.

The sample sample standard deviation is s=3.2 hours.

We now substitute all these values into the formula to obtain:

28.8-2.365(\frac{3.2}{\sqrt{8} } )\:.

26.12\:

We are 95% confident that the population mean is between 26.12 and 31.48  hours.

You might be interested in
Assuming that A and B represent any two​ sets, identify the statement as either always true or not always true.
Fudgin [204]

Step-by-step explanation:

True...it was Answer but not in always

8 0
2 years ago
Kendra can make 120 soccer kicks in 3 minutes. Jovani can make 100 soccer kicks in 4 minutes. How long will it take them to make
meriva

Answer:

Step-by-step explanation:

10 mins

4 0
3 years ago
A student charges $31.50 for 3 hours of babysitting. If the amount the student earns babysitting is proportional to the hours sp
vodomira [7]

Answer:

C) y is equal to 10.5x

Step-by-step explanation:

$31.50 is charged for <em>3  </em>hours so, for 1 hour we need to divide 31.50 by 3, which results in 10.50. So 1 hour of babysitting is $10.50

this is because x is equal to the number of hours they babysit. we do not know the actual so it is replaced with x

and y is equal to the sum of 10.5x because we multiply the number of hours worked, and the amount per hour.

7 0
3 years ago
Find the value of x. If necessary, round to the nearest tenth.
Ghella [55]

Answer:

x = 10.3 in

Step-by-step explanation:

To find the value of a, use the area formula for a triangle. The formula is A = 1/2 *b*h. Here b = x and h= x. The formula becomes A = 1/2 *x². Substitute A = 53 and solve for x by using inverse operations.

A = 1/2x²

53 = 1/2x²

106 = x²

√106 = x

10.3 = x

5 0
3 years ago
What is the missing length?
Alika [10]
The missing length is 51.5, I hope this helps :)
8 0
3 years ago
Read 2 more answers
Other questions:
  • How do you do this question
    5·2 answers
  • Find the area of a square with length 6 1/3 inches. <br> usethe appropriate unit of measurment
    13·1 answer
  • I dont know how to find a .
    7·1 answer
  • A deli spread goes for $6.40 per pound how much do you have to pay for 24 ounces
    5·2 answers
  • Which equation represents the graphed function?
    9·1 answer
  • Helppp
    11·1 answer
  • 1. So far, Marta has correctly predicted the winner of 6 out of 13 football games. She wants to know how many consecutive games
    12·1 answer
  • A university lecture hall has 100 seats. During class, 30% of the seats are empty. How many students are attending class?
    6·2 answers
  • Five more than twice a certain number​
    7·2 answers
  • Y=4x-2 fill in the table using this function rule
    6·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!