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
ad-work [718]
4 years ago
10

A researcher wants to know if the average time in jail for robbery has increased from what it was when the average sentence was

7 years. he obtains data on 400 more-recent robberies and finds an average time served of 7.5 years. find a 95% confidence interval for the average time served (assume jail time follows a normal distribution with standard deviation 3 years).
Mathematics
1 answer:
kati45 [8]4 years ago
5 0

At 95% confidence interval, the z score is 1.96. Using the formula:

Confidence Interval = x ± z s / sqrt (n)

where x is the average time served, s is standard deviation and n is number of samples

 

Confidence interval = 7.5 ± (1.96 * 3) / sqrt (400)

Confidence interval = 7.5 ± 0.294

<span>Confidence interval = 7.206 to 7.794</span>

You might be interested in
The table below shows the amount of money needed to buy certain amounts of fabric. Fabric Cost Fabric (yards) Total Cost (dollar
Ipatiy [6.2K]

Answer:

I believe the answer to be 20. Just looking at the Ratios. So the answer is 20

Step-by-step explanation:

4 0
3 years ago
What is a division expression for the fraction 7/9 ?
konstantin123 [22]

Division expression: 7 divided by 9
8 0
3 years ago
I need the solution
Vikki [24]

Answer:

=3/4

Step-by-step explanation:

3 (c+d)         2c-2d

-------------- * -------------

(c-d)             8c+8d


Factor the right had term.  The numerator can factor out a 2 and the denominator can factor out an 8.

3 (c+d)         2(c-d)

-------------- * -------------

(c-d)             8(c+d)

We can cancel the (c+d) in the numerator the left and the denominator on the right.  We can cancel the (c-d) in the numerator on the right and the denominator on the left

3                  2

-------------- * -------------

1                   8

We can divide the fraction on the right by 2 on the top and bottom.

3                  1

-------------- * -------------

1                   4

=3/4

4 0
4 years ago
2x + 2 y = -2<br> 3x - 2y = 12
Serggg [28]

Answer:

x=2 and y=-6 aka. (2,-6) which is the point of intersection

Step-by-step explanation:

Use elimination to cancel out y by adding the equations:

5x=10

x=2

Plug x=2 into one of the equations and find y:

2(5)+2y=-2

10+2y=-2

2y=-12

y=-6

Therefore, x=2 and y=-6

6 0
3 years ago
4. Find the standard from of the equation of a hyperbola whose foci are (-1,2), (5,2) and its vertices are end points of the dia
Ad libitum [116K]

The <em>standard</em> form of the equation of the hyperbola that satisfies all conditions is (x - 2)²/4 - (y - 2)²/5 = 1 .

<h3>How to find the standard equation of a hyperbola</h3>

In this problem we must determine the equation of the hyperbola in its <em>standard</em> form from the coordinates of the foci and a <em>general</em> equation of a circle. Based on the location of the foci, we see that the axis of symmetry of the hyperbola is parallel to the x-axis. Besides, the center of the hyperbola is the midpoint of the line segment with the foci as endpoints:

(h, k) = 0.5 · (- 1, 2) + 0.5 · (5, 2)

(h, k) = (2, 2)

To determine whether it is possible that the vertices are endpoints of the diameter of the circle, we proceed to modify the <em>general</em> equation of the circle into its <em>standard</em> form.

If the vertices of the hyperbola are endpoints of the diameter of the circle, then the center of the circle must be the midpoint of the line segment. By algebra we find that:

x² + y² - 4 · x - 4 · y + 4= 0​

(x² - 4 · x + 4) + (y² - 4 · y + 4) = 4

(x - 2)² + (y - 2)² = 2²

The center of the circle is the midpoint of the line segment. Now we proceed to determine the vertices of the hyperbola:

V₁(x, y) = (0, 2), V₂(x, y) = (4, 2)

And the distance from the center to any of the vertices is 2 (<em>semi-major</em> distance, a) and the semi-minor distance is:

b = √(c² - a²)

b = √(3² - 2²)

b = √5

Therefore, the <em>standard</em> form of the equation of the hyperbola that satisfies all conditions is (x - 2)²/4 - (y - 2)²/5 = 1 .

To learn more on hyperbolae: brainly.com/question/27799190

#SPJ1

5 0
2 years ago
Other questions:
  • Help im a stuck stick in the mud with this picture attached
    12·1 answer
  • 2 and 3 help please
    6·1 answer
  • I NEED HELP PLS
    14·1 answer
  • Please help me! I do not understand how to do this.
    8·1 answer
  • The algebraic expression for​ "the quotient of 73 and​ x" is
    9·1 answer
  • What is 25% less than a number
    11·1 answer
  • The perimeter of the rectangle is 28 units.
    5·1 answer
  • (a)
    7·1 answer
  • 100 divided by 12? as a fraction<br> no wrong answers
    13·1 answer
  • Evelyn has a summer babysitting job that pays $12 per hour. She wants to know how many hours she has to babysit to afford a new
    13·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!