7th grade math for easy points

What is the first quartile, Q1, of the data set? {36, 45, 79, 80, 82, 85, 90} Enter your answer in the box. Q1 =

MrRa [10]

The upper quartile is, Q1, is 45. The lower quartile, Q2, is 85. The interquartile range is 40. I hope this helps!

8 0

3 years ago

What graph represents the piecewise function?

adoni [48]

Answer: Lower left corner

A piecewise function is basically a combination of other functions to make one single function. We can break up the given piecewise function into two parts:

f(x) = x-4

OR

f(x) = -2x

The f(x) will change depending on what x happens to be. If x is 0 or smaller, then we go with f(x) = x-4. Otherwise, if x is larger than 0, then we opt for f(x) = -2x.

To graph this, we basically graph y = x-4 and y = -2x together on the same coordinate system. We only graph y = x-4 if x is 0 or smaller. Likewise, we graph y = -2x when x > 0. This results in the graph shown in the lower left corner of your four answer choices.

Note: the closed circle means "include this point as part of the graph". The open circle means "exclude this point as part of the graph". So this is why the upper right corner is very close but not quite the answer we want.

5 0

3 years ago

(CO 4) In a sample of 8 high school students, they spent an average of 24.8 hours each week doing sports with a sample standard

AveGali [126]

Answer:

(22.12, 27.48)

Step-by-step explanation:

Given : Significance level : $\alpha: 1-0.95=0.05$

Sample size : n= 8 , which is a small sample (n<30), so we use t-test.

Critical values using t-distribution: $t_{n-1,\alpha/2}=t_{7,0.025}=2.365$

Sample mean : $\overline{x}=24.8\text{ hours}$

Standard deviation : $\sigma=3.2\text{ hours}$

The confidence interval for population means is given by :-

$\overline{x}\pm t_{n-1,\alpha/2}\dfrac{\sigma}{\sqrt{n}}$

i.e. $24.8\pm(2.365)\dfrac{3.2}{\sqrt{8}}$

$24.8\pm2.67569206001\\\\\approx24.8\pm2.68\\\\=(24.8-2.68, 24.8+2.68)=(22.12, 27.48)$

Hence, the 95% confidence interval, assuming the times are normally distributed.= (22.12, 27.48)

6 0

2 years ago

The table includes points on a quadratic function used to model the shape of a hole for one support beam at a new building site.

erastovalidia [21]

The hole is 8 feet deep at ground level ⇒ 3rd answer

Step-by-step explanation:

The form of the quadratic function is y = ax² + bx + c, where

a is the coefficient of x²
b is the coefficient of x
c is the y-intercept (at x = 0)

The vertex point of the quadratic is (h , k), where $h=\frac{-b}{2a}$

and k is the value of y when x = h

The table:

→ x : -2 , 0 , 2

→ y : -6 , -8 , -6

∵ x represents distance from hole's center in feet

∵ y represents the depth from level ground

∴ The quadratic function is y = ax² + bx + c

∵ c is the value of y at x = 0 ⇒ y-intercept

- From the table at x = 0 ⇒ y = -8

∴ c = -8

- Substitute its value in the function model

∴ y = ax² + bx - 8

- To find the values of a and b substitute x and y in the model by

the coordinates of the point in the table

∵ x = -2 and y = -6

∴ -6 = a(-2)² + b(-2) - 8

∴ -6 = 4a - 2b - 8

- Add 8 to both sides

∴ 2 = 4a - 2b

- Switch the two sides

∴ 4a - 2b = 2 ⇒ (1)

∵ x = 2 and y = -6

∴ -6 = a(2)² + b(2) - 8

∴ -6 = 4a + 2b - 8

- Add 8 to both sides

∴ 2 = 4a + 2b

- Switch the two sides

∴ 4a + 2b = 2 ⇒ (2)

Now we have a system of equation to solve it

Add equations(1) and (2) to eliminate b

∵ 8a = 4

- Divide both sides by 8

∴ a = 0.5

- Substitute value of a in equation (1) or to to find b

∵ 4(0.5) + 2b = 2

∴ 2 + 2b = 2

- Subtract 2 from both sides

∴ 2b = 0

- Divide both sides by 2

∴ b = 0

Substitute the values of a and b in the function model

∴ y = 0.5x² + (0)x - 8

∴ y = 0.5x² - 8

∵ y represents the depth from level ground

∵ The vertex of the function model is (h , k)

∴ The deep of the hole at ground level is the value of k

∵ $h=\frac{-b}{2a}$

∴ $h=\frac{-(0)}{2(0.5)}$

∴ h = 0

∵ k is the value of y when x = h

- From the table at x = 0 ⇒ y = -8

∴ k = -8

- Ignore the sign (-) because the k represents the depth of the

hole in feet

∴ The deep of the hole at ground level is 8 feet

The hole is 8 feet deep at ground level

Learn more:

You can learn more about the quadratic function in brainly.com/question/1332667

#LearnwithBrainly

4 0

3 years ago

Find AB, given that line AD is the perpendicular bisector of BC

astraxan [27]

Answer:

AB = 9

Step-by-step explanation:

The perpendicular bisector divides Δ ABC into 2 congruent triangles, that is

Δ ABD ≅ Δ ACD , then

AB = AC = 9

5 0

3 years ago