Answer:
The 95% confidence interval for the proportion of respondents who say the internet has strengthened their relationship with family and friends is  , in which n is the size of the sample.
, in which n is the size of the sample.
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
, and a confidence level of  , we have the following confidence interval of proportions.
, we have the following confidence interval of proportions.

In which
z is the z-score that has a p-value of  .
.
67% of internet users said the internet has generally strengthened their relationship with family and friends.
This means that 
95% confidence level
So  , z is the value of Z that has a p-value of
, z is the value of Z that has a p-value of  , so
, so  .
. 
The lower limit of this interval is:

The upper limit of this interval is:

The 95% confidence interval for the proportion of respondents who say the internet has strengthened their relationship with family and friends is  , in which n is the size of the sample.
, in which n is the size of the sample.