For Exercises 8.49 to 8.51, see page 437; for 8.52 and 8.53, see pages 439–440; for 8.54 to 8.56, see page 440; for 8.57 to 8.58, see page 444; for 8.59, see page 445; and for 8.60, see page 447.
8.55 Social media and the supply chain using plus four.
Refer to the previous exercise and to Example 8.8. Suppose that the sample sizes were smaller but that the proportions remained approximately the same. Specifically, assume that 17 out of 20 small companies used social media and 13 out of 25 large companies used social media. Compute the plus four interval for 95% confidence. Then, compute the corresponding interval and compare the results.
8.55
The plus-four interval is (0.052, 0.548). The interval is (0.079, 0.581). The intervals are somewhat different when the sample sizes are small.