Answer:
The confidence limits for the proportion that plan to vote for the Democratic incumbent are 0.725 and 0.775.
Step-by-step explanation:
In a sample with a number n of people surveyed with a probability of a success of
, and a confidence level of
, we have the following confidence interval of proportions.

In which
z is the zscore that has a pvalue of
.
Of the 500 surveyed, 350 said they were going to vote for the Democratic incumbent.
This means that 
80% confidence level
So
, z is the value of Z that has a pvalue of
, so
.
The lower limit of this interval is:

The upper limit of this interval is:

The confidence limits for the proportion that plan to vote for the Democratic incumbent are 0.725 and 0.775.
Answer:

Step-by-step explanation:

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Answer:
Opt. 1 -3 ≤ x ≤ 3
Step-by-step explanation:
Inequalities are regions, the attached picture shows us a region located between -3 and 3, the dots used are solid, this means that the value '3' is include in the region.
Hence the variable is narrowed to -3 and 3.
Answer:
2
Step-by-step explanation:
denominearar this hard