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
UkoKoshka [18]
2 years ago
14

An ammunition producer claims his best product has an average lifespan of exactly 18 years. A skeptical product evaluator asks f

or evidence (data) that might be used to evaluate this claim. The product evaluator was provided data collected from a random sample of 50 people who used the product. Using the data, an average product lifespan of 15 years and a standard deviation of 8 years was calculated. Select the 90%, confidence interval for the true mean lifespan of this product.
Mathematics
1 answer:
DochEvi [55]2 years ago
8 0

Answer:

The 90% confidence interval for the true mean lifespan of this product is between 13.1 and 16.9 years.

Step-by-step explanation:

We have the standard deviation for the sample, which means that the t-distribution is used 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 = 50 - 1 = 49

90% confidence interval

Now, we have to find a value of T, which is found looking at the t table, with 49 degrees of freedom(y-axis) and a confidence level of 1 - \frac{1 - 0.9}{2} = 0.95. So we have T = 1.6766

The margin of error is:

M = T\frac{s}{\sqrt{n}} = 1.6766\frac{8}{\sqrt{50}} = 1.9

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 15 - 1.9 = 13.1 years

The upper end of the interval is the sample mean added to M. So it is 15 + 1.9 = 16.9 years

The 90% confidence interval for the true mean lifespan of this product is between 13.1 and 16.9 years.

You might be interested in
What is the measurements the for the angles
koban [17]
The angle TQS is 74° and the angle SQR is 106°
5 0
2 years ago
Wha is the area of a rectangle with vertices at (4, 3), (11, 3), (11,9), and (4, 9)?
Butoxors [25]

Answer:

42 units^2.

Step-by-step explanation:

We are given that it is a rectangle so its area is the product of the length of adjacent sides.

Length  of the horizontal line = 11 - 4 = 7 units ( from the first 2 points) and  the length of an adjacent side is 9 - 3 = 6 units (from the second and third points).

Area = 7 * 6 = 42.

8 0
3 years ago
Read 2 more answers
The ratio of boys to girls in a class is 4:3. there are 9 girls. how many boys are in the class?
aalyn [17]
For every 3 girls, there are 4 boys. if there are nine girls, that expands to three extra boys, because for every three theres an extra one. so there are 12 boys (9+3.) the final ratio, boys to girls, is 12:9.
6 0
3 years ago
4380 rounded to the nearest 100​
maks197457 [2]

4,400

The number 3 is in the hundredths place the 8 is behind the 3 so it’s larger than 5 so you turn the 3 into a 4(4,400) and turn all the numbers behind zero (4,400).

4 0
3 years ago
Read 2 more answers
With these numbers I have to find the median. Please help mee!!
Aloiza [94]
Write them in order from least to greatest,
11.9, 12.0, 12.3, 12.4, 12.4, 12.5, 12.7,12.8, 12.9, 13.1, 13.2, 13.8
then eliminate one from each side until you find the middle one,
12.5, 12.7
you have two middle, so you find the middle number in between them.

12.6 is the median.
4 0
3 years ago
Read 2 more answers
Other questions:
  • a square painting has an area of 81x^2-90x-25. A second square painting has an area of 25x^2+30x+9. What is an expression that r
    5·1 answer
  • What is 10 times as much as 700?
    5·2 answers
  • 60000ft² divided by 3 floors and 2 buildings is? How much each floor for each building?
    7·1 answer
  • Find the hieght of the tree​
    10·2 answers
  • Solve using order of operations 24 ÷ 3 (5 - 3)
    5·2 answers
  • True or false: the height is always twice the length of the base edge for any triangular pyramid
    11·1 answer
  • Halle el valor de "h" del punto centro de la ecuación de la circunferencia cuyo diámetro es el segmento de la recta que une los
    10·1 answer
  • Whats 2 1/3 - 1 3/4 in simplest form
    5·1 answer
  • Which expression is equivalent to<br> (5^-2)(5^-1)<br> A. -1/125<br> B. -1/5<br> C.1/125<br> D.1/5
    7·1 answer
  • Estimate 874,238 – 228,759 using front-end estimation.
    15·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!