1. The Philippine Management Association wishes to have information on the mean income of middle managers in the retail industry. A random sample of 256 managers reveals a sample mean of 45,420. The standard deviation of this sample is 2,050. Construct a 95% confidence interval estimate of the true population mean income managers in the retail industry. Interpret your results. 2. The manager of the Popular Grocery Store wants to estimate the mean amount of time spent per shopping visit by customers. A sample of 20 customers reveals the following time spent per visit. 48.16 42.22 46.82 51.45 23.78 41.86 54.86 37.92 52.64 48.59 50.82 46.94 61.83 61.69 49.17 61.46 51.35 52.68 58.84 43.88 What is the best estimate of the population mean (use alpha=.05) 3. A market survey was conducted to estimate the proportion of homemakers who would recognize the brand name of a cleanser based on the shape and the color of the container. Of the 1,400 homemakers sampled, 420 were able to identify the brand by name. Develop a 99 percent confidence interval for the population proportion.