Which of the following conditions must be met in order to make a statistical inference about a population based on a sample
1 answer:
Answer:
For this case if we want to conclude that the sample does not come from a normally distributed population we need to satisfy the condition that the sample size would be large enough in order to use the central limit theoream and approximate the sample mean with the following distribution:
For this case the condition required in order to consider a sample size large is that n>30, then the best solution would be:
n>= 30
Step-by-step explanation:
For this case if we want to conclude that the sample does not come from a normally distributed population we need to satisfy the condition that the sample size would be large enough in order to use the central limit theoream and approximate the sample mean with the following distribution:
For this case the condition required in order to consider a sample size large is that n>30, then the best solution would be:
n>= 30
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i ) 3(2x - 3) = 4(2x + 4)
ii )2(x + 2) + 5(x + 5) = 4(x-8) + 2(x - 2)
2. 3x /4 - 7 /4 = 5x + 12
cancel 4 from both sides
3. x +7 - 8x/3 = 17/6 - 5x/8
put x = 4
L.H.S. = R.H.S.
<h2>--------------------</h2>4. Let 3 consecutive integers : x , x+1 , x+2
As per the question : 2x + 3(x+1) + 4(x+2) = 56
9x + 11 = 56
Transpose 11 to RHS
9x = 45
Divide both sides by 9
x = 5 ,
x + 1 = 5 + 1 = 6
x + 2 = 5 + 2 = 7
Numbers are 5 , 6 and 7 .
<h2>-----------------------</h2>5. Let the age of Jane’s younger sister is x.
Age of Jane will be x + 6
As per the question, after 10 years the sum of their ages will be 50.
After 10 years,
age of Jane = x + 16
age of her younger sister = x + 10
Therefore,
x + 16 + x +10 = 50
2x + 26 = 50
2x = 24
x = 12
Thus, the present age of Jane’s younger sister is 12 years.
And of Jane’s is 12 + 6 = 18 years.
<h2>---------------------</h2>6. Let the breadth of rectangular swimming pool be x metres.
Then, its length = (2x + 2) metres.
We know that the Perimeter of a rectangle
= 2(Length + Breadth)
= 2(2x + 2 + x) = 6x + 4
According to the given condition, we have
6x + 4 = 154
6x = 154 − 4
6x = 150
[Dividing both sides by 6]
x = 25
Thus, breadth = 25 m and
length = 25 × 2 + 2 = 52 m .
<h2>---------------------</h2>7. Let the digit in ten's .
Place be x and the digit in the one's place be y.
x − y = 5 ⟶ (i)
Two digit number = 10x + y
Two digit after reversing the digits = 10y + x
According to question ,
10x + y + 10y + x = 99
11x + 11y = 99
x + y = 9 ⟶ (ii)
On adding (i) and (ii),
2x = 14
x = 7
Putting the value of x in equation (i)
x − y = 5
y = 2
Number = 10x + y
=72 .
<h2>-----------------------</h2>8. Let the speed of the steamer in still water be x km/h.
Then , the speed downstream = (x+2) km/h
and the speed upstream = (x−2) km/h
Given , distance covered in 4 hours downstream = distance covered in 5 hours upstream
4(x + 2) = 5(x − 2)
4x + 8 = 5x − 10
4x − 5x = − 10 − 8
[Transposing 5x to LHS and 8 to RHS]
−x = −18 or x = 18 km/h .
<h2>-----------------------</h2>9. Let the number of notes of different denomination be x.
∴ Numbers of Rs 100 notes , 50 notes and Rs 10 notes will be 2x , 3x and 5x respectively.
Amount of 100 Rs notes ⇒Rs 100 × 2x = 200x
Amount of 50 Rs notes ⇒Rs 50 × 3x = 150x
Amount of 10 Rs notes ⇒Rs 10 × 5x = 50x
As per the question
Total amount = 400000
200x + 150x + 50x = 400000
400x = 400000 , x = 1000
No of Rs 100 notes = 2x = 2 × 1000 = 2000
No of Rs 50 notes = 3x = 3 × 1000 = 3000
No of Rs 10 notes = 5x = 5 × 1000 = 5000 .
<h2>------------------------</h2>10. Let the age of the man be x
Then age of his son becomes (x − 24)
2 years later from now,
Age of man will be = x + 2
and age of his son will be = (x − 24 + 2) = x − 22
According to question,
2(x − 22) = x + 2
i.e., 2x − 44 = x + 2
i.e., x = 46
Therefore ,
Present age of man = 46 years
And present age of his son = 46 − 24 = 22 years .
Answer:
Area = 370 m²
Cost to paint = £105
Step-by-step explanation:
Area of the wall of a cinema hall = Area of a trapezoid (1)+ Area of a rectangle (2) + Area of a trapezoid (3)
Area of a trapezoid =
where and
are the parallel sides and h is the distance between these sides.
Area of trapezoid (1) =
= 69 m²
Area of the rectangle (2) = Length × Width
= 12 × 15
= 180 m²
Area of the trapezoid (3) =
= 121 m²
Now area of the wall = 69 + 180 + 121
= 370 m²
One tin covers the area = 25 m²
Number of tins required to paint the wall =
=
= 14.8
Therefore, number of tins to be purchased = 15
Cost to paint the complete wall = 15 × £7
= £105
