After years of rapid growth, illegal immigration into the United States has decl
ID: 3125434 • Letter: A
Question
After years of rapid growth, illegal immigration into the United States has declined, perhaps owing to the recession and increased border enforcement by the United States (Los Angeles Times, September 1, 2010). While its share has declined, California still accounts for 23% of the nation’s estimated 11.1 million undocumented immigrants.
In a sample of 50 illegal immigrants, what is the probability that more than 20% live in California? (Round “z” value to 2 decimal places, and final answer to 4 decimal places.)
In a sample of 200 illegal immigrants, what is the probability that more than 20% live in California? (Round “z” value to 2 decimal places, and final answer to 4 decimal places.)
After years of rapid growth, illegal immigration into the United States has declined, perhaps owing to the recession and increased border enforcement by the United States (Los Angeles Times, September 1, 2010). While its share has declined, California still accounts for 23% of the nation’s estimated 11.1 million undocumented immigrants.
Explanation / Answer
A) N = 50
P = 0.23
Q = 77
MEAN = NP = 11.5
STANDARD DEV = (NPQ)^(1/2) = 2.97
MORE THEN 20% = P(X>10)
For x = 10, z = (10 - 11.5) / 2.97 = -0.5
Hence P(x > 10) = P(z > -0.5) = [total area] - [area to the left of 0.5]
= 1 - 0.6915 = 0.308
B) N = 200
P = 0.23
Q= 0.77
MEAN = NP = 46
STANDARD DEV = 5.95
P(X>40) =
For x = 40 z = (40 - 46) / 5.95 = -1
Hence P(x > 40) = P(z > -1) = [total area] - [area to the left of -1]
= 1 - 0.1584 = 0.8413