At the World Cup, 25% of the teams are from South American countries. If there are 40 teams in the World Cup, how many are from
2 answers:
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Answer:
The margin of error for the 99% confidence level for this sample is ±2.23.
None of the given figures is close to the answer:
E. None of the above
Step-by-step explanation:
margin of error (ME) around the mean can be calculated using the formula
ME= where
- z is the corresponding statistic of the 99% confidence level (2.576)
- s is the population IQ standard deviation (15)
- N is the sample size (300)
Using these numbers we get:
ME= ≈ 2.23
Answer: Lattice parameter, a = (4R)/(√3)
Step-by-step explanation:
The typical arrangement of atoms in a unit cell of BCC is shown in the first attachment.
The second attachment shows how to obtain the value of the diagonal of the base of the unit cell.
If the diagonal of the base of the unit cell = x
(a^2) + (a^2) = (x^2)
x = a(√2)
Then, diagonal across the unit cell (a cube) makes a right angled triangle with one side of the unit cell & the diagonal on the base of the unit cell.
Let the diagonal across the cube be y
Pythagoras theorem,
(a^2) + ((a(√2))^2) = (y^2)
(a^2) + 2(a^2) = (y^2) = 3(a^2)
y = a√3
But the diagonal through the cube = 4R (evident from the image in the first attachment)
y = 4R = a√3
a = (4R)/(√3)
QED!!!
