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Deffense [45]
3 years ago
6

One hundred teachers attended a seminar on mathematical problem solving. The attitudes of representative sample of 12 of the tea

chers were measured before and after the seminar. A positive number for change in attitude indicates that a teacher's attitude toward math became more positive. The twelve change scores are as follows. 3; 7; −1; 1; 0; 5; −3; 2; −1; 6; 5; −2
Mathematics
2 answers:
velikii [3]3 years ago
7 0

Answer:

1. <u>μ = 1.83 (rounding to the next hundredth)</u>

2. <u>σ = 3.21 (rounding to the next hundredth)</u>

3. <u>Median = 3/3 = 1.5</u>

4. <u>Score = - 5.232</u>

Correct statement and question:

One hundred teachers attended a seminar on mathematical problem solving. The attitudes of a representative sample of 12 of the teachers were measured before and after the seminar. A positive number for change in attitude indicates that a teacher's attitude toward math became more positive. The 12 change scores are as follows:

3; 7; −1; 1; 0; 5; −3; 2; −1; 6; 5; −2

1. What is the mean change score?

2. What is the standard deviation for this sample?

3. What is the median change score?

4. Find the change score that is 2.2 standard deviations below the mean.

Source: Previous question that can be found at brainly

Step-by-step explanation:

1. Let's calculate the mean change score, this way:

μ = (3 + 7 + -1 + 2 + 0 + 5 + -3 + 1 + -1 + 6 + 5 + -2)/12

μ = 22/12

<u>μ = 1.83 (rounding to the next hundredth)</u>

2. Let's calculate the standard deviation, this way:

σ² = [(3² - 1.83²) + (7² - 1.83²) + (-1² - 1.83²) +( 1² -1.83²) + (0² - 1.83²) + (5 - 1.83²) + (-3² - 1.83²) + (2² - 1.83²) + ( -1² - 1.83²) + (6² - 1.83²) + (5² - 1.83²) + (-2² - 1.83²=]/12

σ² = 123.67/12

σ² = 10.31

√σ² = √10.31

<u>σ = 3.21 (rounding to the next hundredth)</u>

3. Let's calculate the median change score, this way:

Let's recall that If you have an even set of numbers, average the middle two to find the median, therefore we have:

-3/-2/-1/-1/0/1/2/3/5/5/6/7

Median = (1 + 2)/2

<u>Median = 3/3 = 1.5</u>

4. Let's find the change score that is 2.2 standard deviations below the mean, this way:

Score = 1.83 - 2.2 * 3.21

Score = 1.83 - 7.062

<u>Score = - 5.232</u>

GenaCL600 [577]3 years ago
5 0

Answer:

3

Step-by-step explanation:

Mean = (3+7+-1+1+0+5+-3+2+-1+6+5+-2)/12

= 1.833

median is middle of ordered numbers -3/-2/-1/-1/0/1/2/3/5/5/6/8/7 here between the 6th and the 7th since with even number sample, there is not a unique middle. This would be 1.5

Standard deviation = √ 123.67/12

√10.3

=3.21

the change score that is 2.2 standard deviations below the mean.

1.83 - 2.2(3.21)

= 5.232

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3 years ago
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How do you this question? Please explain.
Nuetrik [128]

Answer:

(C) 2√15

Step-by-step explanation:

Recognize that all the triangles are right triangles, so are similar to each other. In these similar triangles, the ratio of the short side to the long side is the same for all.

... CB/CA = CT/CB

... CB² = CA·CT = 10·6 = 60 . . . . . . . . . . multiply by CA·CB; substitute values

... CB = √60 = 2√15 . . . . . . . take the square root; simplify

_____

<em>Comment on this solution</em>

The altitude to the hypotenuse of a right triangle (CB in this case) divides the hypotenuse into lengths such that the altitude is their geometric mean. That is ...

... CB = √(AC·CT) . . . . as above

This is true for any right triangle — another fact of geometry to put in your list of geometry facts.

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