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lubasha [3.4K]
3 years ago
10

Select the correct answer. Twenty students in Class A and 20 students in Class B were asked how many hours they took to prepare

for an exam. The data sets represent their answers. Class A: {2, 5, 7, 6, 4, 3, 8, 7, 4, 5, 7, 6, 3, 5, 4, 2, 4, 6, 3, 5} Class B: {3, 7, 6, 4, 3, 2, 4, 5, 6, 7, 2, 2, 2, 3, 4, 5, 2, 2, 5, 6} Which statement is true for the data sets?
A: The mean study time of students in Class A is less than students in Class B.
B: The mean study time of students in Class B is less than students in Class A.
C: The median study time of students in Class B is greater than students in Class A.
D: The range of study time of students in Class A is less than students in Class B. E: The mean and median study time of students in Class A and Class B is equal.
Mathematics
2 answers:
Lunna [17]3 years ago
6 0

Answer:

B: The mean study time of students in Class B is less than students in Class A.

Step-by-step explanation:

To find out why answer B is the right answer, I will give you facts from each option.

Option A is false. <em>The mean study time in Class A is 4.8. Meanwhile in Class B it is 4. For Class A, sum up the 20 study times which is 96 and divide them by 20, you will get 4.8 hours of mean study time. For Class B, the sum of the 20 study times is 80, which divided by 20 will be 4. </em>

Option B is True. <em>See previous explanation. </em>

Option C is False. <em>The median study time in Class B is 4. The median study time in Class A is 4.8, </em>

Option D is False. <em>The range in Class A is from 2 to 8. The range in Class B is from 2 to 7. </em>

Option E is False: <em>The mean and median study time of these classes is different.</em>

belka [17]3 years ago
4 0

Answer:

B: The mean study time of students in Class B is less than students in Class A.

Step-by-step explanation:

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A certain article reported the following observations, listed in increasing order, on drill lifetime (number of holes that a dri
aleksklad [387]

Answer:

Sample mean =119.42

Median = 92

25% trimmed mean = 102.42

10% trimmed mean = 95.69

Step-by-step explanation:

Data in increasing order :

12 13 20 23 31 35 40 43 48 49 58 62 66 67 69 71 73 77 78 79 82 85 86 89 91 93 97 99 101 105 106 106 112 117 124 135 139 141 147 159 161 168 183 207 249 262 289 323 388 513

Total no. of observations = 50

Sample mean = \frac{\text{Sum of all observations}}{\text{Total number of observations}}

= \frac{5971}{50} = 119.42

Median: Since we have even number of observation

Median = \frac{1}{2}({25\text{th term} + 26\text{th term}) = \frac{91+93}{2} = 92

10% Trimmed Mean: We remove 5 values from each side

Trimmed set = 35 40 43 48 49 58 62 66 67 69 71 73 77 78 79 82 85 86 89 91 93 97 99 101 105 106 106 112 117 124 135 139 141 147 159 161 168 183 207 249

Trimmed mean =  \frac{\text{Sum of Trimmed Set}}{\text{Total number of observations}} = \frac{4097}{40} = 102.42

25% Trimmed Mean: We remove 12 values from each side.

Trimmed set =  66 67 69 71 73 77 78 79 82 85 86 89 91 93 97 99 101 105 106 106 112 117 124 135 139 141

Trimmed mean =  \frac{\text{Sum of Trimmed Set}}{\text{Total number of observations}} = \frac{2488}{26} = 95.69

6 0
3 years ago
What is the quotient when 4x3 + 2x + 7 is divided by x + 3?
Arte-miy333 [17]

Answer:

The quotient of this division is (4x^2 -12x + 38). The remainder here would be -26.

Step-by-step explanation:

The numerator 4x^3 + 2x + 7 is a polynomial about x with degree 3.

The divisor x + 3 is a polynomial, also about x, but with degree 1.

By the division algorithm, the quotient should be of degree 3 - 1 = 2, while the remainder shall be of degree 1 - 1 = 0 (i.e., the remainder would be a constant.) Let the quotient be a\,x^2 + b\, x + c with coefficients a, b, and c.

4x^3 + 2x + 7 = \left(a\,x^2 + b\, x + c\right)(x + 3).

Start by finding the first coefficient of the quotient.

The degree-three term on the left-hand side is 4 x^3. On the right-hand side, that would be a\, x^3. Hence a = 4.

Now, given that a = 4, rewrite the right-hand side:

\begin{aligned}&\left(4\,x^2 + b\, x + c\right)(x + 3) \cr =& \left(4x^2 + (b\, x + c)\right)(x + 3) \cr =& 4x^2(x + 3) + (bx + c)(x + 3) \cr =& 4x^3 + 12x^2 + (bx + c)(x + 3)\end{aligned}.

Hence:

4x^3 + 2x + 7 = 4x^3 + 12x^2 + (b\,x + c)(x + 3)

Subtract \left(4x^3 + 12x^2\right from both sides of the equation:

-12x^2 + 2x + 7 = (b\,x + c)(x + 3).

The term with a degree of two on the left-hand side has coefficient (-12). Since the only term on the right hand side with degree two would have coefficient b, b = -12.

Again, rewrite the right-hand side:

\begin{aligned}&\left(-12 x + c\right)(x + 3) \cr =& \left(-12 x+ c\right)(x + 3) \cr =& (-12x)(x + 3) + c(x + 3) \cr =& -12x^2 -36x + (bx + c)(x + 3)\end{aligned}.

Subtract -12x^2 -36x from both sides of the equation:

38x + 7 = c(x + 3).

By the same logic, c = 38.

Hence the quotient would be (4x^2 - 12x + 38).

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3 years ago
Jonathan spins the spinner 10 times. What is the theoretical probability that it stops on the black sector on the last spin?
gayaneshka [121]
1 over 4. It asks for the last spin only.
7 0
3 years ago
What is the GCF of 28x3 and 28x5?
Sergio039 [100]

Answer:

28x^3

Step-by-step explanation:

8 0
2 years ago
Kylie explained that (negative 4 x + 9) squared will result in a difference of squares because (negative 4 x + 9) squared = (neg
Eva8 [605]

Given:

The given expression is:

(-4x+9)^2

According to Kylie,

(-4x+9)^2=(-4x)^2+(9)^2

(-4x+9)^2=16x^2+81

To find:

The correct statement for Kylie's explanation.

Solution:

We have,

(-4x+9)^2

According to the perfect square trinomial (a+b)^2=a^2+2ab+b^2.

(-4x+9)^2=(-4x)^2+2(-4x)(9)+(9)^2

(-4x+9)^2=16x^2-72x+81

Kylie did not understand that this is a perfect square trinomial, and she did not determine the product correctly.

Therefore, the correct option is C.

4 0
3 years ago
Read 2 more answers
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