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Volgvan
3 years ago
11

Suppose we have collected times, in minutes, that it takes volunteers to complete a set of pencil and paper mazes. Volunteers ar

e randomly assigned to one of two groups. Group 1 watch a 5 minute video explaining good strategies for completing the mazes. Group 2 watch a 5 minute video of other people successfully completing the mazes, but with no explanation given.Researchers are interested in testing against the null hypothesis that there is no difference in population mean times that it takes people to complete mazes after watching either type of video.There are the summary statistics after collecting data. Note that the sample sizes differ, because some subjects did not follow instructions correctly and so they were not included in the analysis.x1 = 11.98, x2 = 9.15s1 = 8.69, s2 = 7.75n1 = 43, n2 = 52a. Is this an experimental or observational study?
Mathematics
1 answer:
Leto [7]3 years ago
3 0

Answer:

Is an experimental study

Step-by-step explanation:

In an observational study you don't control any aspect of the investigation you just observe the variables that you determined since the beginning without any intervention.

In this case you are controlling who sees one or the other video, then you are controlling one of the variables that is the type of video each group sees and because of this it is an experimental study. Researchers designed an experiment to prove the null hypothesis they had.

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Ice cream usually comes in 1.5-quart boxes (48 fluid ounces), and ice cream scoops hold about 2 ounces. However, there is some v
Troyanec [42]

Answer:

(a) The expected value and standard deviation of the amount of ice cream served at the party are 54 ounces and 1.25 ounces respectively.

(b) The expected value and standard deviation of the amount of ice cream left in the box after scooping out one scoop are 46 ounces and 1.031 ounces respectively.

(c) Because the variance of each variable is dependent on the other.

Step-by-step explanation:

The random variable <em>X</em> and <em>Y</em> are defined as follows:

<em>X</em> = amount of ice cream in the box

<em>Y</em> = amount of ice cream scooped out

The information provided is:

E (X) = 48

SD (X) = 1

V (X) = 1

E (Y) = 2

SD (Y) = 0.25

V (Y) = 0.0625

(a)

The total amount of ice-cream served at the party can be expressed as:

<em>X</em> + 3<em>Y</em>.

Compute the expected value of (<em>X</em> + 3<em>Y</em>) as follows:

E(X+3Y)=E(X)+3E(Y)\\= 48+(3\times2)\\=48+6\\=54

Compute the variance of (<em>X</em> + 3<em>Y</em>) as follows:

V(X+3Y) = V (X)+3^{2}V(Y)+2\times 3Cov (X,Y)\\=1+(9\times0.0625)+0\\=1.5625

Then the standard deviation of (<em>X</em> + 3<em>Y</em>) is:

SD(X + 3Y) =\sqrt{V(X + 3Y)}\\\sqrt{1.5625}\\=1.25

Thus, the expected value and standard deviation of the amount of ice cream served at the party are 54 ounces and 1.25 ounces respectively.

(b)

The amount of ice-cream left in the box after scooping out one scoop is represented as follows:

<em>X</em> - <em>Y</em>.

Compute the expected value of (<em>X</em> - <em>Y</em>) as follows:

E(X-Y)=E(X)-E(Y)\\=48-2\\=46

Compute the variance of (<em>X</em> - <em>Y</em>) as follows:

V(X - Y) =V(X)+V(Y)-2Cov(X,Y)\\=1+0.0625-0\\=1.0625

Then the standard deviation of (<em>X</em> - <em>Y</em>) is:

SD(X-Y) =\sqrt{V(X -Y)}\\\sqrt{1.0625}\\=1.031

Thus, the expected value and standard deviation of the amount of ice cream left in the box after scooping out one scoop are 46 ounces and 1.031 ounces respectively.

(c)

The variance of the sum or difference of two variables is computed by adding the individual variances. This is because the variance of each variable is dependent on the others.

7 0
3 years ago
Find the length of the hypotenuse.<br><br> O A. 17/2<br> O B. 5/7<br> O C. 3/2<br> OD. 7/3
Sphinxa [80]

Answer:

Step-by-step explanation:

x = 17√2

3 0
3 years ago
Which operation should you perform first in the expression 12x4 to the 2 power
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Answer:

96

Step-by-step explanation:

12 times 4 gets you 48

48 times 2 gets you 96

7 0
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Consider the diagram and angle measurements shown below.
seropon [69]

Answer: C

Step-by-step explanation:

BECUASE I TOOK THE TEST

3 0
3 years ago
The attendance at a school concert was 578. Admission was $2.00 for adults and $1.50 for children. The total receipts were $985.
tigry1 [53]

Answer:

you have 342 children and 236 adults

Step-by-step explanation:

342 X $1.50 = $513 children

236 X $2.00 = $472 adults

$513 + $472 = $985

8 0
3 years ago
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