In India many more sampling points have been established, and in all countries better survey methods, relying on surveyors knocking on doors rather than asking questions at clinics, have gathered data from more representative samples.
The poll had 1, 538 adult respondents, with a sampling error of three percentage points.
Pollsters surveyed 1, 010 American adults, with a sampling error of three percentage points.
But Scott Zeger, the head of the department of biostatistics at Johns Hopkins, who performed the statistical analysis in the study, points out that clustered sampling is the rule rather than the exception in public-health studies, and that the patterns of deaths caused by epidemics are also very variable by location.
The decline is within the poll's sampling error of plus or minus 3 percentage points.
The survey's sampling error is plus or minus 3 percentage points for the overall sample.
CNN: Obama seeks revisions to Afghanistan plans, sources say
The poll has a sampling error of plus or minus 3 percentage points.
The poll had a sampling error of plus or minus 4 percentage points.
That poll questioned 400 likely Democratic primary voters and has a sampling error of plus or minus 5 percentage points.
The survey of 1, 000 adults was taken Sunday through Tuesday, with a sampling error of plus or minus three percentage points.
The poll has a sampling error of plus or minus 4 percentage points on the question of sending a message with votes.
The survey's overall sampling error is plus or minus 3 percentage points.
The survey's overall sampling error is plus or minus 3 percentage points and plus or minus 6 percentage points for the African-Americans sample.
The survey's sampling error is plus or minus 3 percentage points.
CNN: Poll: Most favor bipartisanship; Democrats, not so much
There was little difference in how Democrats and Republicans responded to the poll, which had a sampling error of plus-or-minus 3 points.
The poll of Democratic voters has a sampling error of plus-or-minus 5 percentage points.
CNN's poll has a sampling error of plus-or-minus 3 percentage points for most questions.
The poll's sampling error is plus or minus 4.5 percentage points for Republicans and 4 percentage points for Democrats.
The survey had a sampling error of plus or minus 3.1 percentage points.
The results of the poll, conducted nationally by telephone between Friday and Sunday, has a sampling error of plus-or-minus 3 percentage points.
The margin of sampling error is plus or minus 3.5 percentage points.
Results for the full sample have a margin of sampling error of plus or minus 3.9 percentage points, it is larger for subgroups.
The Research 2000 poll, which carries a sampling error of plus or minus 3.5 percentage points, also shows 6 percent remain undecided in Missouri.
The poll's sampling error is plus-or-minus 5 percentage points for the Republican respondents, 4.5 percentage points for the Democratic respondents, and 8 percentage points for the African-American Democrat respondents.
When split into parties, the numbers have a sampling error of plus-or-minus 5.5 points.
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