Mathematics, 02.08.2019 07:30 cdubble04

The scores on a psychology exam were normally distributed with a mean of 57 and a standard deviation of 9. a failing grade on the exam was anything 2 or more standard deviations below the mean. what was the cutoff for a failing score? approximately what percentage of the students failed?

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Given:Sample mean= 57

Standard Deviation= 9
score of 59

we go to our standard formula:

(score - mean) / sd = z
(59 - 57) / 9 = z

2/9 = z

0.2222 = z
Failing score cutoff would be equal to Mean - 2SD = 67 - 2(9) = 48 is failing score cutoff.

Answer from: hard564

The cutoff for a failing score is with $22.22\%$ of the students failed.

Following the general formula, $z=\dfrac{\rm Score-Mean}{\rm Standard\;Deviation}$

According to the question, the scores on a psychology exam were normally distributed with a mean of 57 and a standard deviation of 9. A failing grade on the exam was anything 2 or more standard deviations below the mean so,

$z=\dfrac{\rm Score-Mean}{\rm Standard\;Deviation}\\z=\dfrac{2}{9}\\z=0.222$

Also, falling cut-off score is calculated as-

$\rm Falling\;cut-off=Mean-2\times Stand\;Deviation\\\rm Falling\;cut-off=57-2\times 9\\\rm Falling\;cut-off=57-18\\\rm Falling\;cut-off=39$

Hence, cutoff for a failing score is with $22.22\%$ of the students failed.

Learn more about mean and standard deviation here:

link

Answer from: Quest

answer: a video game has three difficulty levels: easy, medium, and expert. the game's scoring works in such a way that a player has to score a fixed number of points to advance to the next level, and then the scoring starts over. the total score needed to clear all three difficulty levels is 7,500. two times the number of points needed to clear the easy level is 500 more than the number of points needed to clear the medium level. twice the number of points needed to clear the medium difficulty level is 1,500 more than the number of points needed to clear the expert level. if x, y, and z represent the easy, medium, and expert levels, respectively, and a is the coefficient matrix of the system of equations modeling this situation, identify the inverse matrix, a-1, and the solution matrix, x, of the system of equations.

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rauschg

rauschg · hand

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Answer from: Quest

r and t.

both are 64 degrees.