Do the side lengths, 7, 20 and 21 form a right triangle? PLEASEEEEE ANSWER

In statistics, what does df denote? If a simple random sample of 22 speeds of cars on California Highway 405 is to be used to

Reil [10]

Answer:

df refers to degrees of freedom.

the specific value of df in the example is 21.

Step-by-step explanation:

In statistics, degrees of freedom is the number of values in the final calculation of a statistic that are free to vary. It is the number of independent ways by which a dynamic system can move, without violating any constraint imposed on it.

In other words, degrees of freedom is the number of independent pieces of information that went into calculating the estimate, and calculated by

n – 1 where “n” is the number of items in your set.

In the question, a simple random sample of 22 speeds of cars on California Highway 405 is to be used to test the claim, thus the number of items in the survey are 22.

From this we get:

df=22-1=21

6 0

3 years ago

A boat on a river travels downstream between two points, 20 mi apart, in one hour. The return trip against the current takes 2 1

kondaur [170]

Answer:

The speed of boat in still water is 14 miles per hour.

The speed of current is 6 miles per hour.

Step-by-step explanation:

Let v represent the speed of boat in still water and c represent speed of current.

We have been given that a boat on a river travels downstream between two points, 20 miles apart, in one hour.

The speed of boat downstream would speed of boat in still water plus speed of current that is $(v+c)$ .

The return trip against the current takes 2 1/ 2 hours. The speed of boat against current would speed of boat in still water minus speed of current that is $(v-c)$ .

$\text{Speed}=\frac{\text{Distance}}{\text{Time}}$

Substituting our given values, we will get:

$v+c=\frac{20}{1}...(1)$

$v-c=\frac{20}{2.5}...(2)$

Adding both equations, we will get:

$v+c+(v-c)=\frac{20}{1}+\frac{20}{2.5}$

$v+c+v-c=\frac{20}{1}+\frac{20}{2.5}$

$2v=20+8$

$2v=28$

$\frac{2v}{2}=\frac{28}{2}$

$v=14$

Therefore, the speed of boat in still water is 14 miles per hour.

To find the speed of the current in the river, we will substitute $v=14$ in equation (1) as:

$14+c=\frac{20}{1}$

$14+c=20$

$14-14+c=20-14$

$c=6$

Therefore, the speed of current is 6 miles per hour.

3 0

3 years ago

What is the quotient (3x3 + 10x2 + 10x + 4) ÷ (x + 2)?

grandymaker [24]

The correct choice is B
3x^2 + 4x + 2

4 0

4 years ago

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An arts and crafts store sells sheets for stickers. Use the table to write an equation you can use to find the total cost y in d

nikitadnepr [17]

X=1/2+y this is the answer

4 0

3 years ago

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What is the coefficient of the term 13a in the expression 13a+6b? Please Help Fast alot of points

KATRIN_1 [288]

Answer:

13

Step-by-step explanation:

A coefficient is the contestant value (a number) placed before a variable to be multiplied. A coefficient is multiplied by it's neighboring variable. In '13a', 13 is being multiplied by a.

13 will be the coefficient in 13a.

3 0

3 years ago