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SpyIntel [72]
3 years ago
10

HELP MATH QUESTIONS!! WILL MARK CORRECT ANSWERS BRAINLIEST!! 40 POINTS!! DUE TODAY ASAP!!

Mathematics
1 answer:
yuradex [85]3 years ago
3 0

Answer:

  1. f(x) = 34.59 +3.74x
  2. 0.96
  3. very strong
  4. 8.93

Step-by-step explanation:

1. The selection of answers offers a choice of positive or negative slope, a slope of about 4 or about 35, and y-intercepts from the same set of values.

If you consider a couple of points (at the ends of the domain is usually a good choice), you see the slope is about 4 and the y-intercept is around 30.

For example, the points (5, 50) and (15, 91) have a slope of (91-50)/(15-5) = 4.1 so will give rise to the equation ...

  y -50 = 4.1(x -5)

Filling in x=0 gives y = 50 -20.5 = 29.5

So, the nearest of the offered choices is ...

  f(x) = 34.59 +3.74x

Please note that no calculator is involved. We simply estimated the parameters of the regression line based on a couple of the data points. This estimate is sufficient to allow us to find the correct answer choice.

__

2. If we look at a few other data points, we see that they have a generally upward trend that matches the above equation pretty well. That suggests a very high value of correlation, so the appropriate choices would be 0.93 or 0.96. Of course, the correlation is positive, matching the sign of the slope of the regression line. (Since the data points do not fall exactly on a line, the correlation is not 1.00. My assessment is they fall close enough to the line to rate a correlation of .96 instead of .93.)

At this point, the output of your calculator can confirm that the correlation coefficient is closer to 0.96. Mine says r = 0.9624.

  r = 0.96

__

3. We have already determined by examining the data points that the correlation is "very strong." The correlation coefficient of 0.96 confirms this.

__

4. Using the equation of part 1, we can find the number of study hours:

  68 = 34.59 +3.74x

  (68 -34.59)/3.74 = x ≈ 8.933

We expect a score of 68 is associated with about 8.93 study hours.

_____

Please note that we have used very little calculation to determine the answers to this question. The only requirement is a general understanding of what linear regression and correlation coefficients mean.

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In a recent test, you scored 1.0 standard deviations above the average score attained, and the scores are normally distributed.
sesenic [268]

Answer:

97.75 %

Step-by-step explanation:

You score 1 standard deviation above the mean

a) we have from left tail up to the mean 50 % of all values

b) We have in the interval  [ μ  -  σ  ;  μ  +  σ ] 95.5 % of all possible values, if we divide that 95.5 by 2 we get 47.75 %,  the part of the values that correspond to the right, then in order to get the  % of students scored lower we add

50  +  47.75   = 97.75 %

So you can say that the porcentage of students that scored lower than you is 97.75 %

3 0
3 years ago
Work out the value of 5x8 x 5-2/5x4
Alisiya [41]

Answer:

=6

Step-by-step explanation:

(5×8)×(5-2)/(5×4)

Numerator =40×3

=120

Denominator = 5×4

=20

simplifying 120/20

=6

5 0
2 years ago
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Help plz it’s urgent
vfiekz [6]

Answer:

3. 18 + 18 + 7 + 7 = 50

4. 120 degrees

Step-by-step explanation:

7 0
3 years ago
the standard form of the equation of a parabola is y=x^2 -8x + 29. what is the vertex form of the equation?
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4 0
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Janaya buys a postcard from each travel destination she visits. Before starting her travels this year, Janaya had 20 postcards.
MrRa [10]

Answer:

The percentage increase in Jayana's postcard collection is 15%

Step-by-step explanation:

Jayana had 20 postcards last year

With 3 more postcards this year

From the given equation Quantity = Percent x Whole

Here;

Let P = Percent/100%

Quantity = Increment in postcard = 3 postcards

Whole = The total postcards from last year = 20 postcards

Hence,

3 postcards = P x 20 postcards

P = 3/20 = 0.15

Recall P = Percent/100%

∴ Percent = P x 100% = 0.15 x 100% = 15%

The percentage increase in Jayana's postcard collection is 15%

4 0
2 years ago
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