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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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A rectangle is shown below.
Dahasolnce [82]

Answer:

  a)  247.25 cm²

  b)  62.0 cm

Step-by-step explanation:

All of these upper-bound/lower-bound problems are worked the same way. The bounds on the measurement are presumed to be half of one unit of the least-significant digit.

Here, the least significant digit of both numbers is in the "units" place, so the maximum error is presumed to be 1/2 unit, or ±0.5 cm.

If the measurement were 7.36 inches, the least significant digit is in the hundredths place, so the maximum error is presumed to be half a hundredth, or ±0.5 × 0.01 inches = ±0.005 inches.

__

To find the bounds on the measurement, you add or subtract this maximum error from the measurement. So, for the measurements in this problem, the maximum and minimum they can be are ...

  21 cm: minimum of 21 - 0.5 = 20.5 cm; maximum of 21 + 0.5 = 21.5 cm

  11 cm: minimum of 10.5 cm; maximum of 11.5 cm

If you wanted to express these as an inequality, you'd have to remember that half-units are rounded up, so the inequalities would be ...

  20.5 cm ≤ long side < 21.5 cm

  10.5 cm ≤ short side < 11.5 cm

__

a) The area is computed as the product of the rectangle's side length measurements. The area will be a maximum when both measurements are a maximum:

  Amax = (21.5 cm)(11.5 cm)

  Amax = 247.25 cm²

__

b) The perimeter is twice the sum of the lengths of two adjacent sides of the rectangle. The minimum perimeter will be the sum using the minimum side lengths, or ...

  Pmin = 2(20.5 cm +10.5 cm) = 2(31.0 cm)

  Pmin = 62.0 cm

_____

<em>Comment on measurement bounds</em>

You have to remember that these concepts are mathematical in nature, so only an approximation of the real world. If you have ever used a tape measure to measure a distance of any length, you will have discovered a couple of things:

  • different tape measures are different lengths
  • the measurement you make depends on how tight you stretch the tape (and often, on temperature and/or humidity)
  • it is amazingly hard to choose the "nearest" measurement when the value is halfway between marks on the tape. (That is, there is some fuzziness in the boundary between nearest units.)

So, mathematically, there will be very specific definitions and procedures to follow regarding measurement values. In the real world, you have to remember these are only an approximation to reality, hopefully a useful one.

7 0
3 years ago
the drill must go 3/8 of the way through the sheet the sheet is 2.5 cm thick how deep should the drill be set
andrey2020 [161]

Answer:

15/16 cm

Step-by-step explanation:

The drill must go 3/8 of the way from one side of the sheet to the other.  The depth that this drill must reach is found by multiplying 2.5 cm by 3/8:

25       3       5         3

----- * ----- = ------ * ------ = 15/16 cm

10       8        2        8

7 0
3 years ago
Which line has an undefined slope? A y = 0 B y = 2 C x = y D x = 2
PolarNik [594]
Learn this :
VUX -- vertical line, undefined slope, represented by x = a number.
HOY -- horizontal line, 0 slope, represented by y = a number

so the line with the undefined slope is going to be  x = 2
5 0
3 years ago
Read 2 more answers
How many pop-cones would you have to buy to equal the volume of an extra large tub?
SOVA2 [1]

Answer:

around 15

Step-by-step explanation:

if you divide the volume of the big 10 dollar cylinder popcorn by the volume of the 0.99 cone popcorn which is 785/ 52.36 its 14.9923605806

4 0
3 years ago
17 more than some number is 57
anastassius [24]
17+x=57.
So, subtract 17 from both sides
X=40
6 0
3 years ago
Read 2 more answers
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