Question 21.16

image 21.16 The effect of sample size. A December 2014 CBS News/New York Times poll found that 52% of its sample thought that basic medical care in the United States was affordable. Give a 95% confidence interval for the proportion of all adults who feel this way, assuming that the result comes from a sample of size

  1. (a) n = 750.

  2. (b) n = 1500.

  3. (c) n = 3000.

  4. (d) Explain briefly what your results show about the effect of increasing the size of a sample on the width of the confidence interval.