Answer:
An 80% confidence interval for the proportion of companies that are planning to increase their workforce is 0.033 < p < 0.331.
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
.
Only 2 of the 11 companies were planning to increase their workforce
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:

An 80% confidence interval for the proportion of companies that are planning to increase their workforce is 0.033 < p < 0.331.