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
8_murik_8 [283]
2 years ago
13

A study is done to find the 95% confidence interval for the difference in means between the ACT scores between two schools in a

given city. One school had a random sample of 39 students had a sample mean of 25.90 with a sample standard deviation of 3.49. The second school had a random sample of 37 students had a sample mean 27.70 with a sample standard deviation of 2.47. What is the lower bound of the 95% confidence interval for the difference in means
Mathematics
1 answer:
Kitty [74]2 years ago
7 0

Solution :

95% confidence interval for the difference between the means of ACT scores between two schools, is given by :

$[(\overline X_1 - \overline X_2)-ME, (\overline X_1 - \overline X_2)+ME]$

$\overline X_1 = 25.90 ,  \ \ \ \overline X_2 = 27.70$

$S_1=3.49, \ \ \ S_2 = 2.47$

$n_1=39, \ \  n_2=37$

M.E. , Margin of error,

$=t_{n_1+n_2-2,0.025} \times \left( s \sqrt{\frac{1}{n_1}+\frac{1}{n_2}}$

$s^2 = \frac{(n_1-1)S_1^2+(n_2-1)S^2_2}{n_1+n_2-2}$

  $=\frac{38(3.49)^2+36(2.47)^2}{39+37-2}$

 = 9.222

s = 3.03

$t_{74,0.05} = 1.99$

$M.E. = 1.99 \times 3.03 \times \sqrt{\frac{1}{39}+\frac{1}{37}}$

        = 1.4

Therefore, 95% CI = [(25.90-27.70) - 1.4 , (25.90-27.70) + 1.4]

                              = [-3.2, -0.4]

Therefore, the lower bound is -3.2

You might be interested in
Please help to fill in the fractions 2/8=.../4
mote1985 [20]
1 because if you divide 2/8 by 2, you will get 1/4.
4 0
2 years ago
Read 2 more answers
What is the answer to math problem ×2÷3
Rashid [163]
THE answer is 0.66 repeating 9 times
then 7
5 0
3 years ago
Read 2 more answers
Describe the graph of the functions y=|x+2|
inn [45]

To obtain the graph of the function y = |x+2| we have to make a table of values of x to find the values of y. The absolute value or modulus of a real number is its numerical value without care its sign. For example, the absolute value of |4| and |-4| is 4.

In order to make a graph we are going to use the values (-3, -2, -1, 0, 1, 2, 3) for x.

x = -3

y = |-3 + 2| = |-1| = 1

x = -2

y = |-2 + 2| = |0| = 0

x = -1

y = |-1 + 2| = |1| = 1

x = 0

y = |0 + 2| = |2| = 2

x = 1

y = |1 + 2| = |3| = 3

x = 2

y = |2 + 2| = |4| = 4

x = 3

y = |3 + 2| = |5| = 5

<u>  x   ║   y</u>

-3        1

-2        0

-1         1

 0        2

 1         3

 2        4

 3        5

Obtaining the graph shown in the image attached.

.

7 0
3 years ago
Mr. Helsley wishes to save atleast $1500 in 12 months. If he saved $300 during the first 4 months, what is the least possible av
faust18 [17]

Answer:he must save an average of $150 or more in each of the remaining 8 months.

Step-by-step explanation:

Mr. Helsley wishes to save at least $1500 in 12 months. If he saved $300 during the first 4 months, then the amount left would be

≥ 1500 - 300

Let x represent the least possible average amount that he must save in each of the remaining 8 months. This means that the total amount that he would save in the last 8 months would be 8x. Therefore,

300 + 8x ≥ 1500

8x ≥ 1500 - 300

8x ≥ 1200

x ≥1200/8

x ≥ 150

3 0
3 years ago
John has $220 in his account and adds $25 to it each month Cheryl has $100 in her account and adds $35 each to her account. How
sammy [17]

Answer: In 12 months they will have the same amount, which will be $520.

Step-by-step explanation:

220 + 25m = 100 + 35m

m = month

Subtract 100 from each side

120 + 25m = 35m

Subtract 25m from each side

120 = 10m

Divide each side by 10

12 = m

4 0
3 years ago
Read 2 more answers
Other questions:
  • Three rational numbers between 5/31 and 6/31
    8·1 answer
  • Find height of this cylinder
    6·1 answer
  • 32. Factor the following Quadratic:<br> x2 + 4x - 12
    13·1 answer
  • In graph, the area below f(x) is shaded and labeled A, the area below g(x) is shaded ad labeled B, and the area where f(x) and g
    11·1 answer
  • Two sides of a triangle have the same length. The third side measures 2 m less than twice the common length. The perimeter of th
    8·1 answer
  • And here are the answer choices
    14·2 answers
  • Please answer for me domain and range
    5·1 answer
  • 3.) If you deposit $4,000 for 6 years at a simple interest rate of 6%, how much will be in the account?
    7·1 answer
  • I need help asap!!!!!!!
    15·1 answer
  • Please hurry not much more time answer even if its too late somebody else can use the answer.
    6·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!