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kirill [66]
2 years ago
10

Alice wants to prove to her parents that listening to music while she does her homework will help her get better grades. She dec

ides to ask 25 of her friends if they listen to music while they do their homework and what their grades are. She finds that her friends who have high grades also listen to music while they do their homework. She tells her parents that she has proven that listening to music while doing homework will cause her grades to improve. What mistake has Alice made?
A) She did not separate her friends into different groups, and she didn't apply a treatment.
B) She did not separate her friends into different groups, and she used a survey to collect data.
Mathematics
1 answer:
Leona [35]2 years ago
8 0
The answer would be A.

Explanation: First off, she did not separate her friends into different groups. Secondly, she only got information from the students who listen to music. She should've gotten information from the students who don't listen to music in order to compare her results. She needed to make the survey equal meaning that, she needed to survey the students who listen to music and the ones that don't.
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Sienna is solving the quadratic equation by completing the square. 3x2 + 9x – 4 = 0 3x2 + 9x = 4 A(x2 + 3x) = 4 What is the valu
bogdanovich [222]

Answer:

I am going to show you the first steps to complete squares for the given equation: 1) Starting equation: 3x^2 + 9x -4 = 0 2) Add 4 to both sides => 3x^2 + 9x - 4 + 4 = 4 => 3x^2 + 9x = 4 3) Extract common factor 3 in the left side => 3 (x^2 + 3x). Now, compare with a(x^2 + 3x) and you get a = 3. Answer: a = 3.

3 0
2 years ago
Read 2 more answers
A population consists of the following five values: 1, 3, 4, 4, and 6. List all samples of size 2 from left to right without rep
aniked [119]

Answer:

The sample of sizes 2 and their mean are given below.

Step-by-step explanation:

The population consist of  5 values, S = {1, 3, 4, 4, 6}.

The number of samples of size 2 (without replacement) that can be formed from these 5 values is:

{5\choose 2}=\frac{5!}{2!(5-2)!} =10

Th formula to compute the mean is:

\bar x=\frac{1}{n}\sum x_{i}

List the 10 samples and their mean as follows:

<u>Sample</u>                       <u>Mean</u>

(1, 3)                    \bar x=\frac{1}{2}[1+3]=\frac{4}{2}=2.0

(1, 4)                    \bar x=\frac{1}{2}[1+4]=\frac{5}{2}=2.5

(1, 4)                    \bar x=\frac{1}{2}[1+4]=\frac{5}{2}=2.5

(1, 6)                    \bar x=\frac{1}{2}[1+6]=\frac{7}{2}=3.5

(3, 4)                   \bar x=\frac{1}{2}[3+4]=\frac{7}{2}=3.5

(3, 4)                   \bar x=\frac{1}{2}[3+4]=\frac{7}{2}=3.5

(3, 6)                   \bar x=\frac{1}{2}[3+6]=\frac{9}{2}=4.5

(4, 4)                   \bar x=\frac{1}{2}[4+4]=\frac{8}{2}=4.0

(4, 6)                   \bar x=\frac{1}{2}[4+6]=\frac{10}{2}=5.0

(4, 6)                   \bar x=\frac{1}{2}[4+6]=\frac{10}{2}=5.0

8 0
2 years ago
The following observations are on stopping distance (ft) of a particular truck at 20 mph under specified experi- mental conditio
zzz [600]

Answer:

see explaination

Step-by-step explanation:

Data : 32.1 , 30.6 , 31.4 , 30.4 , 31.0 , 31.9

Mean X-bar = 31.23

SD = 0.689

a)

Null Hypothesis : Xbar = mu

Alternate Hypothesis : Xbar > mu

z = (Xbar - mu) / (SD/sqrt(n))

= (31.23 - 30 ) /(0.689/sqrt(6))

= 4.372

P-value = ~0

Since P-vale < 0.01 , we will reject null hypothesis.

The data suggest that true average stopping ditance exceeds the maximum.

b)

i) SD = 0.65

mu = 31

z = (Xbar - mu) / (SD/sqrt(n))

= (31.23 - 31) /(0.65/sqrt(6))

= 0.867

P-value = 0.3859 Answer

ii) SD = 0.65

mu = 32

z = (Xbar - mu) / (SD/sqrt(n))

= (31.23 - 32) /(0.65/sqrt(6))

= -2.9

P-value = 0.0037 Answer

c)

i) SD = 0.8

mu = 31

z = (Xbar - mu) / (SD/sqrt(n))

= (31.23 - 31) /(0.8/sqrt(6))

= 0.704

P-value = 0.4814 Answer

ii) SD = 0.8

mu = 32

z = (Xbar - mu) / (SD/sqrt(n))

= (31.23 - 32) /(0.8/sqrt(6))

= -2.357

P-value = 0.0184 Answer

The probabilities obtained in part c are comparatively higher than that of part b.

d)

i) For alpha =0.01

z = (Xbar - mu) / (SD/sqrt(n))

=> -2.32 = (31.23 - 31) /(0.65/sqrt(n))

=> (0.65/sqrt(n)) = (31.23 - 31)/-2.32

=> sqrt(n) = (0.65*(-2.32)) / (31.23 - 31)

=> n = 43 Answer

ii) For beta =0.10

z = (Xbar - mu) / (SD/sqrt(n))

=> -1.28 = (31.23 - 31) /(0.65/sqrt(n))

=> (0.65/sqrt(n)) = (31.23 - 31)/-1.28

=> sqrt(n) = (0.65*(-1.28)) / (31.23 - 31)

=> n = 13 Answer

4 0
2 years ago
Terry made a plastic birdhouse with the dimensions shown below. How many square inches
xxMikexx [17]

Answer:

376 squared inches for the hole bird house, 60 for the side with the whole.

Step-by-step explanation:

1 side is 60 inches squared, another is 48 inches squared, and another is 80 inches squared, and there are two of each side so you get 120+96+160= 376.

7 0
2 years ago
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What is the relationship between two lines whose slopes are −8 and 1 8 ?
zavuch27 [327]

Answer:

They are perpendicular lines

Step-by-step explanation:

If one line has slope -8 and the other one has slope 1/8, they must be perpendicular to each other because the condition for perpendicular lines is that the slope of one must be the "opposite of the reciprocal of the slope of the original line."

the opposite of -8 is 8 , and the reciprocal of this is 1/8

5 0
2 years ago
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