Answer:
Step-by-step explanation:
Ok, so we have to help your pupil (lets call her Jane) figure out "why researchers should use a random sample to conduct a survey". So, i will list all of the choices.
- A random sample is likely to avoid bias
- In a random sample some members of the population are more likely to be selected than others
- Random samples provide consistency and systematically favor one choice over every other choice in each survey question
- Random sampling will provide a more representative sample of population
- Researchers can use a random sample to draw conclusions about the population
Random sampling is used to get the best average, and not favor any one opinion. For example, if you were trying to figure out the daily spending budget of people, you wouldn't just go to the upper clas part with all the rich people, you would survey from all over the town to get results from all kinds of people. So, the answers are:
- A random sample is likely to avoid bias (because thats exactly what they do)
- Random sampling will provide a more representative sample of population (because they are designed to do that)
- Researchers can use a random sample to draw conclusions about the population (thats why they take the samples)
Hope this helps
The total area of the complete lawn is (100-ft x 200-ft) = 20,000 ft².
One half of the lawn is 10,000 ft². That's the limit that the first man
must be careful not to exceed, lest he blindly mow a couple of blades
more than his partner does, and become the laughing stock of the whole
company when the word gets around. 10,000 ft² ... no mas !
When you think about it ... massage it and roll it around in your
mind's eye, and then soon give up and make yourself a sketch ...
you realize that if he starts along the length of the field, then with
a 2-ft cut, the lengths of the strips he cuts will line up like this:
First lap:
(200 - 0) = 200
(100 - 2) = 98
(200 - 2) = 198
(100 - 4) = 96
Second lap:
(200 - 4) = 196
(100 - 6) = 94
(200 - 6) = 194
(100 - 8) = 92
Third lap:
(200 - 8) = 192
(100 - 10) = 90
(200 - 10) = 190
(100 - 12) = 88
These are the lengths of each strip. They're 2-ft wide, so the area
of each one is (2 x the length).
I expected to be able to see a pattern developing, but my brain cells
are too fatigued and I don't see it. So I'll just keep going for another
lap, then add up all the areas and see how close he is:
Fourth lap:
(200 - 12) = 188
(100 - 14) = 86
(200 - 14) = 186
(100 - 16) = 84
So far, after four laps around the yard, the 16 lengths add up to
2,272-ft, for a total area of 4,544-ft². If I kept this up, I'd need to do
at least four more laps ... probably more, because they're getting smaller
all the time, so each lap contributes less area than the last one did.
Hey ! Maybe that's the key to the approximate pattern !
Each lap around the yard mows a 2-ft strip along the length ... twice ...
and a 2-ft strip along the width ... twice. (Approximately.) So the area
that gets mowed around each lap is (2-ft) x (the perimeter of the rectangle),
(approximately), and then the NEXT lap is a rectangle with 4-ft less length
and 4-ft less width.
So now we have rectangles measuring
(200 x 100), (196 x 96), (192 x 92), (188 x 88), (184 x 84) ... etc.
and the areas of their rectangular strips are
1200-ft², 1168-ft², 1136-ft², 1104-ft², 1072-ft² ... etc.
==> I see that the areas are decreasing by 32-ft² each lap.
So the next few laps are
1040-ft², 1008-ft², 976-ft², 944-ft², 912-ft² ... etc.
How much area do we have now:
After 9 laps, Area = 9,648-ft²
After 10 laps, Area = 10,560-ft².
And there you are ... Somewhere during the 10th lap, he'll need to
stop and call the company surveyor, to come out, measure up, walk
in front of the mower, and put down a yellow chalk-line exactly where
the total becomes 10,000-ft².
There must still be an easier way to do it. For now, however, I'll leave it
there, and go with my answer of: During the 10th lap.
Answer:
B. no, it is not low enough
A. no, it is not low enough
Step-by-step explanation:
Given that Air-USA has a policy of booking as many as 24 persons on an airplane that can seat only 22.
Prob for a random person booked arrive for flight = 0.86
No of persons who books and arrive for flight, X is binomial, since there are two outcomes and each person is independent of the other
The probability that if Air-USA books 24 persons, not enough seats will be available
= P(X=23)+P(x=24)
= 0.1315
B. no, it is not low enough
-------------------------------
The prob we got is >10% also
A. no, it is not low enough
Answer:
Step-by-step explanation:
ABC and DEF are parallel lines. So, ∠ABE and ∠BED are co interior angles.
∠ABE + ∠BED = 180 {SUM OF CO INTERIOR ANGLE IS 180}
∠ABE+ 110.2 = 180
∠ABE = 180 - 110.2
∠ABE = 69.8
Now, ABC is straight line
∠ABE + ∠EBG + ∠CBG = 180
69.8 + ∠EBG + 34.8 = 180
104.6 + ∠EBG = 180
∠EBG = 180 - 104.6
∠EBG = 75.4
Again, DEF is straight line
∠DEB + ∠BEG + ∠GEF = 180
110.2 + ∠BEG + 25.6 = 180
∠BEG + 135.8 = 180
∠BEG = 180 - 135.8
∠BEG = 44.2
In triangle BEG,
∠BEG + x + ∠EBG = 180 { sum of all angles of triangle is 180}
44.2 + x + 75.4 = 180
x + 119.6 = 180
x = 180 - 119.6
x = 60.4
