Somehow i got 2.5 guess i am wrong...
Is there supposed to be an attached image for us to see?
Answer:
B
Step-by-step explanation:
The correct answer is A.) { - 0.79 ; 1.08 }, because
<span><span> <span>For </span><span>ax^2 + bx + c = 0</span><span>, the value of </span>x<span> is given by:</span></span> <span> ;
a = - 7 ; b = 2 ; c = 6 ;
b^2 - 4ac = 4 + 168 = 172 ; </span></span>

≈ 13.11 ;<span><span>
x 1 = ( - 2 + 13.11 ) / (- 14) = 11.11 / ( - 14 ) </span></span>≈<span><span> -0.79 ;
x = 2 = ( - 2 - 13.11 ) / ( - 14 ) = (-15.11) / (- 14 ) </span></span>≈ 1.08 ;<span><span>
</span></span>
Using the normal distribution, it is found that 58.97% of students would be expected to score between 400 and 590.
<h3>Normal Probability Distribution</h3>
The z-score of a measure X of a normally distributed variable with mean
and standard deviation
is given by:

- The z-score measures how many standard deviations the measure is above or below the mean.
- Looking at the z-score table, the p-value associated with this z-score is found, which is the percentile of X.
The mean and the standard deviation are given, respectively, by:

The proportion of students between 400 and 590 is the <u>p-value of Z when X = 590 subtracted by the p-value of Z when X = 400</u>, hence:
X = 590:


Z = 0.76
Z = 0.76 has a p-value of 0.7764.
X = 400:


Z = -0.89
Z = -0.89 has a p-value of 0.1867.
0.7764 - 0.1867 = 0.5897 = 58.97%.
58.97% of students would be expected to score between 400 and 590.
More can be learned about the normal distribution at brainly.com/question/27643290
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