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2 years ago

Results for a 20-point multiple choice math quiz are as follows: 9 students scored a 20,4 students

Mathematics

1 answer:

Ray Of Light [21]2 years ago

3 0

Answer:

18 1/2 or 37/2

Step-by-step explanation:

To calculate the average of something, we add the numbers and divide by the count of those numbers. In this case, we have this as the sum of the numbers:

9 × 20 + 4 × 19 + 3 × 18 + 5 × 17 + 12

And the number of students as the count:

9 + 4 + 3 + 5 + 1

Now to calculate that out:

(9 × 20 + 4 × 19 + 3 × 18 + 5 × 17 + 12)/(9 + 4 + 3 + 5 + 1) ⇒

(180+76+54+85+12)/(9+4+3+5+1) ⇒

407/22 ⇒

37/2⇒

18 1/2

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Step-by-step explanation: Because Median is all the numbers put in order least to greatest. Then the middle number.

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3 years ago

Area of a circle? Need to know for big test tomorrow

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3 years ago

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Mrs. Blalock gave her students a math test. Each problem on the test was worth 4.5 points. The grade on the test, y, can be calc

umka2103 [35]

Answer:

4,5*16=y

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Step-by-step explanation:

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3 years ago

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A data set with a mean of 34 and a standard deviation of 2.5 is normally distributed

tresset_1 [31]

Answer:

a) $z= \frac{34-34}{2.5}= 0$

$z= \frac{39-34}{2.5}= 2$

And we want the probability from 0 to two deviations above the mean and we got 95/2 = 47.5 %

b) $P(X$

$z= \frac{31.5-34}{2.5}= -1$

So one deviation below the mean we have: (100-68)/2 = 16%

c) $z= \frac{29-34}{2.5}= -2$

$z= \frac{36.5-34}{2.5}= 1$

For this case below 2 deviation from the mean we have 2.5% and above 1 deviation from the mean we got 16% and then the percentage between -2 and 1 deviation above the mean we got: (100-16-2.5)% = 81.5%

Step-by-step explanation:

For this case we have a random variable with the following parameters:

$X \sim N(\mu = 34, \sigma=2.5)$

From the empirical rule we know that within one deviation from the mean we have 68% of the values, within two deviations we have 95% and within 3 deviations we have 99.7% of the data.

We want to find the following probability:

$P(34 < X$

We can find the number of deviation from the mean with the z score formula:

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

And replacing we got

$z= \frac{34-34}{2.5}= 0$

$z= \frac{39-34}{2.5}= 2$

And we want the probability from 0 to two deviations above the mean and we got 95/2 = 47.5 %

For the second case:

$P(X$

$z= \frac{31.5-34}{2.5}= -1$

So one deviation below the mean we have: (100-68)/2 = 16%

For the third case:

$P(29 < X$

And replacing we got:

$z= \frac{29-34}{2.5}= -2$

$z= \frac{36.5-34}{2.5}= 1$

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2 years ago

Val needs to find the area enclosed by the figure. The figure is made by attaching semicircles to each side of a 42-m-42-m squar

oee [108]

The area enclosed by the figure is 4533.48 square meters.

<u>Step-by-step explanation:</u>

Side length of the square = 42m

The semicircle is attached to each side of the square. So the diameter of the semicircle is the length of the square.

Radius of the semicircle = 21m

Area of the square = 42 x 42 = 1764 square meters

Area of 1 semicircle = π(21 x 21) /2

= (3.14) (441) /2

= 1384.74/2

= 692.37 square meters

Area of 4 semicircle = 4 x 692.37

= 2769.48 square meters

Total area = 1764 + 2769.48

= 4533.48 square meters

The area enclosed by the figure is 4533.48 square meters.

7 0

2 years ago