For the three sample sizes we find margins of error are 7.44, 3.58, 1.86.
Larger samples have smaller margins of error.
Increasing the sample size by a factor of 4 means that the margin of error is cut in half. The population in this case could be all hotel managers in hotels of size 200 to 500 in Detroit and Chicago. The CI is wider because we insisted on greater confidence. The central limit theorem indicates that for a large sample we can use the confidence intervals based on the normal distribution no matter what the population distribution. The scale would be judged accurate based on this interval because 100 is contained in the interval.