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Dvinal [7]
3 years ago
5

A research study was performed to determine if more than 30% of first-grade students at one school have entered Piaget’s concret

e operational stage of development. A p-value of .021 was computed and the researchers rejected the null hypothesis. They concluded that more than 30% of first-grade students at this school have entered the concrete operational stage of development. However, a census actually found that in the population of all first graders at this school, only 28% have entered the concrete operational stage. Which of the following occurred in this scenario?a) Type I errorb) Type II error
Mathematics
1 answer:
suter [353]3 years ago
7 0

Answer:

Type I error

Step-by-step explanation:

A type I error occurs if the null hypothesis is rejected when it is actually true.

Type I                                      Type II

Reject null when true           Fail to reject null when not true

Null hypothesis: ∪ = 30%

Alternative hypothesis: ∪ > 30%

The researchers concluded that more than 30% of first-grade students at this school have entered the concrete operational stage of development and they rejected the null hypothesis.

However, a census actually found that in the population of all first graders at this school, only 28% have entered the concrete operational stage.

A type I error has been made because in actuality the null hypothesis was true but was rejected.

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7.
mylen [45]

The cafeteria sold 41 corn chips and 80 potato chips.

Step-by-step explanation:

Let,

Corn chips = x

Potato chips = y

Price of corn chips = $0.80

Price of potato chips = $0.60

According to given statement;

x+y= 121   Eqn 1

0.80x+0.60y=80.80   Eqn 2

Multiplying Eqn 1 by 0.80

0.80(x+y= 121)\\0.80x+0.80y=96.80\ \ \ Eqn\ 3

Subtracting Eqn 2 from Eqn 3

(0.80x+0.80y)-(0.80x+0.60y)=96.80-80.80\\0.80x+0.80y-0.80x-0.60y=16\\0.20y=16

Dividing both sides by 0.20

\frac{0.20y}{0.20}=\frac{16}{0.20}\\y=80

Putting y=80 in Eqn 1

x+80=121\\x=121-80\\x=41

The cafeteria sold 41 corn chips and 80 potato chips.

Keywords: linear equation, subtraction

Learn more about linear equations at:

  • brainly.com/question/4639731
  • brainly.com/question/4655616

#LearnwithBrainly

5 0
4 years ago
Q13 A gardener needs to buy compost to fill this tub.
REY [17]

Answer:

  5 bags

Step-by-step explanation:

The volume of the tub is the product of its dimensions:

  V = (1.8 m)(0.5 m)(0.25 m) = 0.225 m³

There are 1000 L in 1 m³, so this volume in liters is ...

  (0.225 m³)(1000 L/m³) = 225 L

At 50 L per bag, the gardener needs ...

  (225 L)/(50 L/bag) = 4.5 bags

The gardener probably cannot purchase a partial bag, so must buy more than is needed.

The gardener must buy 5 bags of compost to fill the tub.

8 0
3 years ago
If Darlene reads 5/8 of a 56 page book how many pages did she read?
Marina86 [1]
Darlene read 35 pages of the book.
5 0
3 years ago
Read 2 more answers
Find the value of x shown
sveta [45]
2x+56=180

2x=124

X=62
8 0
4 years ago
Read 2 more answers
A manufacturer produces bolts of a fabric with a fixed width. The quantity q of this fabric (measured in yards) that is sold is
slamgirl [31]

Answer:

(A) the selling price is $20 per yards, and the expected yards to be sold is 10,000 yards

the derivative f'(20) is negative, which means the fabric producing company will sell 350 fewer yards when selling price is $20 per yard

(B) = R'(20) = $3000

∴the company will get extra $3000 revenue when selling price is $20 per yard

Step-by-step explanation:

A. given that

<em>f</em>(20)= 10,000

<em>f'</em>(20)= -350(first derivative)

the selling price is $20 per yards, and the expected yards to be sold is 10,000 yards

the derivative f'(20) is negative, which means the higher the price, it wil reduce the number of yards to be sold making it 350 fewer yards

(B) R(p) = p <em>f</em>(p)

<em>f</em>(20)= 10,000

<em>f'</em>(20)= -350(first derivative)

R(p) = p <em>f</em>(p)

differentiate with respect to p, using product rule

R'(p) = p <em>f' </em>(p) + <em>f</em>(p) (first derivative)

where p = 20

R'(20) = 20 <em>f' </em>(20) + <em>f</em>(20)

R'(20) = 20(-350) + 10,000

R'(20) = -7000 + 10,000

R'(20) = $3000

∴ the revenue is increasing by $3000 for every selling sold yard and increase in price per yard

3 0
4 years ago
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