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3 years ago

This is my spring break hw but I don’t understand this question

Mathematics

1 answer:

vladimir1956 [14]3 years ago

5 0

5 + 20 = 25 and that’s the answer

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A professor gives her 100 students an exam; scores are normally distributed. The section has an average exam score of 80 with a

frozen [14]

Answer:

6.18% of the class has an exam score of A- or higher.

Step-by-step explanation:

When the distribution is normal, we use the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the zscore of a measure X is given by:

$Z = \frac{X - \mu}{\sigma}$

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

In this question, we have that:

$\mu = 80, \sigma = 6.5$

What percentage of the class has an exam score of A- or higher (defined as at least 90)?

This is 1 subtracted by the pvalue of Z when X = 90. So

$Z = \frac{X - \mu}{\sigma}$

$Z = \frac{90 - 80}{6.5}$

$Z = 1.54$

$Z = 1.54$ has a pvalue of 0.9382

1 - 0.9382 = 0.0618

6.18% of the class has an exam score of A- or higher.

4 0

2 years ago

The Jayden family eats at a restaurant that is having a 15% discount promotion. Their meal costs $78.85 before the discount, and

erik [133]

Answer:

$80.22

Step-by-step explanation:

4 0

2 years ago

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A girl is half as old as her sister and is also two years younger than her brother. If the sum of the three children's ages is $

Vesna [10]

13 and a half 5 and half and 16

5 0

3 years ago

Evaluate the expression below when y = -3.

Rudik [331]

Start with the given equation:
$2y+7$
Substitute known values:
$2(-3)+7$
Evaluate:
$-6+7=1$

Similarly:
$-4y-10$
$-4(-3)-10$
$12-10=2$

8 0

3 years ago

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using the pythagorean theorem find the area of an equilateral triangle whose side measures 7 units find the area to the nearest

Molodets [167]

<span>If you have an equilateral triangle, the median is also the altitude so - That means that if you draw altitude, it will bisect the base of the triangle and meet at two right angles. That gives you two of the measurements for the right triangle - the side (6) hypotenuse, and the base (3). You can then figure out the height using the Pythagorean as you have the a and the c for the theorem. Then you can use 1/2 base times height to find the area.
</span>

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3 years ago

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