(Using Excel with steps)

There has been rapid growth in the land area planted with high yielding, high protein soybeans particularly suited to local climate, many of which are not genetically modified (non-GMO). A survey of 392 soybean farmers found that 72% of them grew nonGMO soybeans

a) Calculate a 95% confidence interval for this proportion, stating your assumptions clearly.

b) How much wider or narrower would this confidence interval have been if only 98 soybean farmers had been surveyed?