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Ber [7]
3 years ago
14

Sunshine High School claims that 72% of its students complete their homework on a daily basis. Ms. Carter surveyed 80 students a

nd found that only 60% complete their daily homework. What does the test statistic calculation look like in this situation for an appropriate hypothesis test? z equals 0.60 minus 0.72 all over the square root of the quantity 0.72 times 0.28 over 80 z equals 0.60 minus 0.72 all over the square root of the quantity 0.60 times 0.40 over 80
Mathematics
1 answer:
Ulleksa [173]3 years ago
6 0

Answer: z equals 0.60 minus 0.72 all over the square root of the quantity 0.72 times 0.28 over 80

Step-by-step explanation:

let p be the population proportion of students complete their homework on a daily basis.

As per given , we have

p= 0.72

sample size : n= 80

Sample proportion : \hat{p}=0.60

Test statistic for proportion:

z=\dfrac{\hat{p}-p}{\sqrt{\dfrac{p(1-p)}{n}}}

i.e.

z=\dfrac{0.60-0.72}{\sqrt{\dfrac{0.72(1-0.72)}{80}}}

i.e.

z=\dfrac{0.60-0.72}{\sqrt{\dfrac{0.72(0.28)}{80}}}

That is , z equals 0.60 minus 0.72 all over the square root of the quantity 0.72 times 0.28 over 80

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Can you guys help me with this math questions
dimulka [17.4K]

Answer:

2)  $40 per shirt

3)  80/9 m = 8.9 m (nearest tenth)

Step-by-step explanation:

The first question has been answered here: brainly.com/question/27846862

------------------------------------------------------------------------------------------------------

<u>Question 2</u>

Given information:

  • Previous sales = 300 shirts at $20 each
  • For every $1 increase in price, the number of sales diminishes by 5

Let x = number of $1 increases

Let y = total revenue (in dollars)

From the given information:

  • Price change of shirt:  (20 + x)
  • Number of sales change:  (300 - 5x)

Therefore, we can create a <u>quadratic equation</u> with the given information:

\implies y = (20+x)(300-5x)

As we need to find the maximum amount of revenue, we need to find the vertex of y.  As the equation is already factored, the quickest way to do this is to the find the mid-point of the zeros (since a quadratic curve is symmetrical).

\begin{aligned}y & =0\\\implies (20+x)(300-5x) & =0\\\implies (20+x) & =0 \implies x=-20\\\implies (300-5x) & = 0 \implies x=60\end{aligned}

\textsf{Midpoint}=\dfrac{-20+60}{2}=20

Therefore, Sammy should have 20 $1 increases to maximize the revenue, so the new price will be:

\implies \$20 + 20 \times \$1 = \$40\: \sf per\:shirt

------------------------------------------------------------------------------------------------------

<u>Question 3</u>

Given information:

  • Bridge is modeled as a parabola
  • Width of bridge = 30 m
  • Max height of bridge = 10 m high (in the middle)

As the bridge is modeled as a parabola, and we have been given the width and height, we can create a quadratic equation using the vertex form.

Vertex form:  y=a(x-h)^2+k

where:

  • x is the horizontal distance of the bridge
  • y is the height of the bridge
  • (h, k) is the vertex
  • a is some constant

Middle of the bridge = 30 m ÷ 2 = 15 m

Max height of the bridge = 10 m

Therefore, the vertex of the parabola is (15, 10)

\implies y=a(x-15)^2+10

We know that when x = 0, y = 0.  Therefore, substitute these values into the equation and solve for a:

\implies 0=a(0-15)^2+10

\implies 0=225a+10

\implies 225a=-10

\implies a=-\dfrac{10}{225}

\implies a=-\dfrac{2}{45}

Therefore, the equation of the parabola is:

\implies y=-\dfrac{2}{45}(x-15)^2+10 \quad \quad \textsf{for }0\leq x\leq 30

The horizontal distance at 5 m right of the middle is:

\implies \dfrac{30}{2}+5=20\:\sf m

Therefore, to find the height at this point, input x=20 into the equation and solve for y:

\implies -\dfrac{2}{45}(20-15)^2+10=\dfrac{80}{9}\:\sf m

Therefore, the height of the bridge at 5 m to the right of the middle is:

\dfrac{80}{9}\:=8.9\: \sf m\:(nearest\:tenth)

3 0
2 years ago
Angie's grandma live in Cleveland, Ohio,and is going to drive to Minneapolis, Minnesota, to visit Angie and her family. The two
Anna11 [10]

Answer:

376 miles each day

Step-by-step explanation:

If Angie's grandma wants to drive the same distance each day, she can divide her journey in to two equal halves.

The total distance that Angie's grandma has to drive is 752 miles so each day she may need to drive,

\frac{752}{2}=376 miles

Also, it takes 12 hours to drive 752 miles, so the speed at which Angie's grandma should drive is,

\frac{752}{12}=62.667 m/h

At this speed if she drives 6 hours a day, she may need to drive,

d= s \times t= 62.667 \times 6 = 376 miles in a day.

7 0
3 years ago
What is the mathematical process of parabolas and how do they help us in the real world?
Talja [164]

Answer:

parabolas (quadratic curves)

in the real world -

any trajectory of any item that is thrown on earth can be represented as a quadratic equation.

I do not know what you mean by the mathematical process.  

Step-by-step explanation:

7 0
3 years ago
Renting roller blades costs a flate fee of $5 plus an additional $2.50 per hour. Write a linear equation that models this.
Kobotan [32]

Answer:

Linear equation : y = 2.50h + 5

Step-by-step explanation:

Given that:

Fee for renting roller blades = $5

Per hour charges = $2.50

Let,

h be the number of hours roller blades were rented

y be the total amount

Total amount = Per hour charges * Number of hours + Flat fee

y = 2.50h + 5

Hence,

Linear equation : y = 2.50h + 5

4 0
3 years ago
The length of a remote control car is 8 1/2 inches to the nearest half inch and 8 1/4 to the nearest quarter inch . Which measur
zalisa [80]

Answer:

8 1/4 inches

Step-by-step explanation:

If the answer were closer to 8 1/2 inches then when measuring to the nearest quarter inch, the answer would have been 8 1/2. Instead the answer was 8 1/4 because the length was closer to 8 1/4 than it was to 8 1/2.

7 0
3 years ago
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