All categories

4 years ago

Question 1

Mathematics

1 answer:

xxTIMURxx [149]4 years ago

3 0

Answer:

The teacher randomly divides the class into two groups. One of the groups receives computer-based instruction and the other group receives traditional instruction without computers. After instruction, each student takes a test and the teacher wants to compare the test scores of the two groups.

Step-by-step explanation:

A two sample t-test is used to compared the means of two samples who were exposed to different scenarios and therefore, it helps us to see the difference between these two samples.

In this problem, the teacher is experimenting with a new computer-based instruction. To be able to use the two-sample t-test she would have to have two randomly assigned samples and expose each of these two samples to different scenarios (one would receive a traditional instruction and the other one would receive a computer instruction), and finally she would need to compare the scores in both samples.

Therefore, the correct answer would be b) The teacher randomly divides the class into two groups. One of the groups receives computer-based instruction and the other group receives traditional instruction without computers. After instruction, each student takes a test and the teacher wants to compare the test scores of the two groups.

*Option A is incorrect because the students are only exposed to the lesson using a computer program and therefore they aren't exposed to different scenarios.

*Option C is incorrect because although in this case the teacher uses both traditional and computer methods, there are not two different samples and she only gets the opinion of the students which is not an exact method of getting information on the effectiveness of the computer based method.

You might be interested in

2cos^2x+cosx-1=0 Find the degree solutions

Lapatulllka [165]

2cos²x+cos x-1=0

cos x=t

2t²+t-1=0

t=[-1⁺₋√(-1+8)]/2=(-1⁺₋3)/4
We have two possible set solutions:
First set solutions.
t₁=(-1-3)/2=-4/4=-1
cos x=-1 ⇒x=cos⁻¹ (-1)=π +2kπ or 180º+360ºk (k=(...-2,-1,0,1,2...)

Second set solutions:
t₂=(-1+3)/4=2/4=1/2

cos x=1/2 ⇒ x=cos⁻¹ 1/2=π/3+2kπ U 5π/3+ 2kπ or
60º+360ºK U 300º+360ºK (k=...-2,-1,0,1,2,...)

solutions: first set solutions U second set solutions:

Answer in radians : π +2kπ U π/3+2kπ U 5π/3+ 2kπ (k=...-1,0,1,...)
Answer is degrees: 180º+360ºk U 60º+360ºK U 300º+360ºK (k=...-2,-1,0,1,2,...)

4 0

3 years ago

<img src="https://tex.z-dn.net/?f=%20%7Bx%7D%5E%7B4%7D%20%20-%206%20%7Bx%7D%5E%7B3%7D%20%20%2B%2022%20%7Bx%7D%5E%7B2%7D%20%20-%2

alexira [117]

Answer:

x = 2, 1 + 3i, 1 − 3i

Step-by-step explanation:

Find the Roots (Zeros)

x^4 − 6x^3 + 22x^2 − 48x + 40

Set x^4 − 6x^3 + 22x^2 − 48x + 40 equal to 0. x^4 − 6x^3 + 22x^2 − 48x + 40 = 0

Solve for x.

Factor the left side of the equation.

Factor x^4 − 6x^3 + 22x^2 − 48x + 40 using the rational roots test.

(x − 2) (x^3 − 4x^2 + 14x − 20) = 0

Factor x^3 − 4x^2 + 14x − 20 using the rational roots test.

(x − 2) (x − 2) (x2 − 2x + 10) = 0

Combine like factors.

(x − 2)2 (x^2 − 2x + 10) = 0

If any individual factor on the left side of the equation is equal to 0, the entire expression will be equal to 0.

(x − 2)^2 = 0

x^2 − 2x + 10 = 0

Set (x − 2)^2 equal to 0 and solve for x.

Set (x − 2)^2 equal to 0.

(x − 2)^2 = 0

Solve (x − 2)^2 = 0 for x.

x = 2

Set x^2 − 2x + 10 equal to 0 and solve for x.

Set x^2 − 2x + 10 equal to 0. x^2 − 2x + 10 = 0

Solve x^2 − 2x + 10 = 0 for x.

Use the quadratic formula to find the solutions.

−b ± (√b^2 − 4 (ac) )/2a

Substitute the values a = 1, b = −2, and c = 10 into the quadratic formula and solve for x.

2 ± (√(−2)^2 − 4 ⋅ (1 ⋅ 10))/2 ⋅ 1

Simplify.

Simplify the numerator.

x = 2 ± 6i/ 2.1

Multiply 2 by 1

x = 2 ± 6i/2⋅1

Simplify

2 ± 6i/2

x = 1 ± 3i

The final answer is the combination of both solutions.

x = 1 + 3i, 1 − 3i

The final solution is all the values that make (x − 2)2 (x2 − 2x + 10) = 0 true.

x = 2, 1 + 3i, 1 − 3i

3 0

3 years ago

When the members of a family discussed where their annual reunion should take place, they found that out of all the family mem

creativ13 [48]

Answer:

2178

Step-by-step explanation:

We are given that

Number of members would not go to a park=1010

Number of members would not go to a beach=88

Number of members would not go to the family cottage=1212

Number of members would go to a neither a park nor beach=55

Number of members would go to neither a beach nor the family cottage=44

Number of members would go to neither a park nor the family cottage=77

Number of members would not go to a park or a beach or to the family cottage=33

Number of members would go to all three places=11

s=Number of non park goers only

t=Number of non park goers and non beach goers but not non family cottage goers

u=Number of non beach goers only

v=Number of non park goers and non family cottage goers but not non beach goers

w=Number of non park goers, non beach goers and non family cottage goers

x=Number of non beach goers, non family cottage goers but not non park goers

y=Number of non family cottage goers only

z=Number of not non park goers, not non beach goers and not non family cottage goers

According to question

$s+t+v+w=1010$

$t+u+w+x=88$

$v+w+x+y=1212$

$t+w=55$

$w+x=44$

$v+w=77$

$w=33$

$z=11$

$v=77-w=77-33=44$

$t=55-w=55-33=22$

$x=44-w=44-33=11$

$22+u+33+11=88$

$u=88-66=22$

$44+33+11+y=1212$

$y=1212-88=1124$

$s+22+44+33=1010$

$s=1010-99=911$

Total number of family members=s+t+u+v+w+x+y+z=911+1124+22+11+22+44+11+33=2178

Hence, total number of family members=2178

8 0

4 years ago

Rachel is collecting donations for the local animal shelter. So far she has collected $245, which is 70% of what she hopes to co

Nata [24]

Answer:

The money Rachael plan to collect for the shelter is $350.

Step-by-step explanation:

Given:

Rachel is collecting donations for the local animal shelter.

So far she has collected $245, which is 70% of what she hopes to collect.

Now, to find the money Rachael plan to collect for the shelter.

Let the total amount Rachael plan to collect be $x$ .

Amount she collected = $245.

Percentage of amount she collected = 70%.

Now, to get the amount Rachael plan to collect we put an equation:

$70\%\ of\ x=\$245.$

⇒ $\frac{70}{100} \times x=245$

⇒ $0.70\times x=245$

⇒ $0.70x=245$

Dividing both sides by 0.70 we get:

⇒ $x=\$350.$

Therefore, the money Rachael plan to collect for the shelter is $350.

4 0

4 years ago

Name a big reason Europeans came to the “New World” during the fifteenth and sixteenth centuries?

goldfiish [28.3K]

They came because they were looking for new land to agriculture their plants

5 0

3 years ago