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Valentin [98]
3 years ago
9

Which of the following is an example of a matched pairs design? A. A teacher calculates the average scores of students on a pair

of tests and wishes to see if this average is larger than 80%. B. A teacher compares the pre-test and post-test scores of students. C. A teacher compares the scores of students using a computer based method of instruction with scores of other students using a traditional method of instruction. D. A teacher compares the scores of students in her class on a standardized test with the national average score.
Mathematics
1 answer:
Mashutka [201]3 years ago
5 0

Answer:

B. A teacher compares the pre-test and post-test scores of students

Step-by-step explanation:

the answer is true, because it is a good example to compare the tests between students, we know that a matching pair design is a random model and is used when the experiment allows grouping subjects in pairs based on a variable and each pair will receive randomly a different handling, the answer A is not true because in the example all students are uniformly averaged and the variable is not correlated with subgroups, option c is incorrect because the variable was not randomized and generates classification bias and the option d is incorrect because the teacher compares a small sample as her class with a score of a total sample, but does not intervene on her students when selecting the corresponding group

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Plz help!!!!!!!!!!!!!
pantera1 [17]

Answer:

the third one

Step-by-step explanation:

-b to start is -(-6) which is 6

needs the plus and minus

the first expression is the whole numerator

5 0
4 years ago
Read 2 more answers
Find the sum of all natural numbers between 25 and 210 which are either divisible by 3 or divisible by 4? Please let me know ​I
Ray Of Light [21]

Let <em>S</em> be the sum of the integers 25-210:

<em>S</em> = 25 + 26 + 27 + … + 208 + 209 + 210

Let <em>S₃</em>, <em>S₄</em>, and <em>S₁₂</em> denote the sums of the integers in <em>S</em> that are multiples of 3, 4, or 12, respectively. We'll also count how many terms each sum involves; it'll be useful later.

<em>S₃</em> = 27 + 30 + 33 + … + 204 + 207 + 210 … … … (<u>62</u> terms)

<em>S₃</em> = 3 (9 + 10 + 11 + … + 68 + 69 + 70)

<em>S₄</em> = 28 + 32 + 36 + … + 200 + 204 + 208 … … … (<u>46</u> terms)

<em>S₄</em> = 4 (7 + 8 + 9 + … + 50 + 51 + 52)

<em>S₁₂</em> = 36 + 48 + 60 + … + 180 + 192 + 204 … … … (<u>15</u> terms)

<em>S₁₂</em> = 12 (3 + 4 + 5 + … + 15 + 16 + 17)

Let's look at <em>S₃ </em>:

<em>S₃</em> = 3 (9 + 10 + 11 + … + 68 + 69 + 70)

By reversing the order of the sum, we get

<em>S₃</em>* = 3 (70 + 69 + 68 + … + 11 + 10 + 9)

Of course <em>S₃</em> = <em>S₃</em>*, I'm just calling it something else temporarily. Notice that every term in the same position of either sum adds up the same number.

9 + 70 = 79

10 + 69 = 79

11 + 68 = 79

and so on. Then

<em>S₃</em> + <em>S₃</em>* = 3 (79 + 79 + 79 + … + 79 + 79 + 79)

or

2<em>S₃</em> = 3 × <u>62</u> × 79   ==>   <em>S₃</em> = 7,347

We can compute the other two sums in the same way.

<em>S₄</em> = 4 (7 + 8 + 9 + … + 50 + 51 + 52)

<em>S₄</em>* = 4 (52 + 51 + 50 + … + 9 + 8 + 7)

==>   2<em>S₄</em> = 4 × <u>46</u> × 59  ==>   <em>S₄</em> = 5,428

<em>S₁₂</em> = 12 (3 + 4 + 5 + … + 15 + 16 + 17)

<em>S₁₂</em>* = 12 (17 + 16 +15 + … + 5 + 4 + 3)

==>   2<em>S₁₂</em> = 12 × <u>15</u> × 20   ==>   <em>S₁₂</em> = 1,800

Then the sum you want is

<em>S₃</em> + <em>S₄</em> - <em>S₁₂</em> = 10,975

We subtract <em>S₁₂</em> because each of its terms is counted twice (once in <em>S₃</em> and again in <em>S₄</em>).

6 0
3 years ago
Help?- Plot and connect the points A (-4, 4), B (-1, 1), C (-6, 1), and find the length of BC.
horsena [70]
the answer could be D 5 units
because the distance between B and C is 5 by looking at the x-axis
5 0
3 years ago
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A is the poin 3,5 and b is the point 0,k if the distance of ab is 5 units find the possible value of k
JulijaS [17]

Answer:

K is either 9 or 1

Step-by-step explanation:

Sqrt((0 - 3)² + (k - 5)²) = 5

Square both sides

(0 - 3)² + (k - 5)² = 5²

(0 - 3)² + (k - 5)² = 25

-3² + (k - 5)² = 25

9 + (k-5)(k-5) = 25

9 + k² - 5k - 5k + 25 - 25 = 0

k² - 10k +9 = 0

k² - 9k - k + 9 = 0

k(k - 9) - 1(k - 9) = 0

k - 1 = 0 ; k = 1

k - 9 = 9; k = 1

K = 9 or k = 1

K is either 9 or 1

4 0
3 years ago
How do I find the value of X
sesenic [268]
You could either:
a) Use the Pythagorean Theorem
b) Use Sine/Cosine/Tangent Inverse to find one of the angles, and then use that angle to find x.
5 0
3 years ago
Read 2 more answers
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