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3 years ago

On a standardized exam, the scores are normally distributed with a mean of 350 and

Mathematics

1 answer:

kondaur [170]3 years ago

3 0

Answer:

$\boxed {\boxed {\sf z= -0.1}}$

Step-by-step explanation:

A z-score helps describe the relationship between a value and the mean of a group of values. Basically, it tells us how many standard deviations away from the mean a value is. The formula is:

$z= \frac{x- \mu}{\sigma}$

where x is the value, μ is the mean, and σ is the standard deviation.

For this standardized exam, the mean is 350 and the standard deviation is 40. We want to find the z-score for a value of 346.

x= 346
μ= 350
σ= 40

Substitute the values into the formula.

$z= \frac{ 346-350}{40}$

Solve the numerator.

$z- \frac{ -4}{40}$

Divide.

$z= -0.1$

The z score is <u>-0.1</u>, so the person with a score of 346 on the exam was 0.1 standard deviations lower than the mean.

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3 years ago

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Louann and Carla received equal scores on a test made up of multiple choice questions and an essay. Louann got 14 multiple choic

Gnoma [55]

Louann= 14x+24
Carla= 16x+14
So basically this is just like solving equations. The way I did this was just put random numbers for x and then solve it.
First attempt:
14(7)+24=16(7)+14
98+24=112+14
122=126
Okay the first one didn't work so I use 6 for x.
Second attempt:
14(6)+24=16(6)+14
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So 6 didn't work and you already should know that the answers should be between 1 and 5.

So now I going to do 5 for x
Third attempt:
14(5)+24=16(5)+14
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4 years ago

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Which statements about the system are true?

Kruka [31]

2 Answers:

B) The lines are parallel
C) The lines have the same slope.

Parallel lines always have equal slope, but different y intercepts.

==========================================================

Explanation:

Let's solve the second equation for y

3y - x = -7

3y = -7+x

3y = x-7

y = (x-7)/3

y = x/3 - 7/3

y = (1/3)x - 7/3

The equation is in y = mx+b form with m = 1/3 as the slope and b = -7/3 as the y intercept. We see that the first equation, where y was already isolated, also has a slope of m = 1/3. The two equations of this system have the same slope. Choice C is one of the answers.

However, they don't have the same y intercept. The first equation has y intercept b = -4, while the second has b = -7/3. This means that they do not represent the same line. They need to have identical slopes, and identical y intercepts (though the slope can be different from the y intercept of course) in order to have identical lines. So we can rule out choice D and E because of this.

Because the two equations have the same slope, but different y intercepts, this means the lines are parallel. Choice B is the other answer.

Parallel lines never touch or intersect, which in turn means there is no solution point. A solution point is where the lines cross. We can rule out choice A.

I recommend using your graphing calculator, Desmos, GeoGebra, or any graphing tool (on your computer or online) to graph each equation given. You should see two parallel lines forming. I used GeoGebra to make the graph shown below.