A marketing researcher wants to estimate the mean amount spent ($) on Amazon.com by Amazon Prime member shoppers. Suppose a random sample of 100 Amazon Prime member shoppers who recently made a purchase on Amazon.com yielded a mean of $1,500 and a standard deviation of $200.

1. Construct a 95% confidence interval estimate for the mean spending for all Amazon Prime member shoppers.
2. Interpret the interval constructed in (a).

A survey of nonprofit organizations showed that online fundraising has increased in the past year. Based on a random sample of 133 nonprofits, the mean one-time gift donation resulting from email outreach in the past year was $87. Assume that the sample standard deviation is $9.

1. Construct a 95% confidence interval estimate for the population mean one-time gift donation.
2. Interpret the interval constructed in (a).

A cellphone provider has the business objective of wanting to estimate the proportion of subscribers who would upgrade to a new cellphone with improved features if it were made available at a substantially reduced cost. Data are collected from a random sample of 500 subscribers. The results indicate that 135 of the subscribers would upgrade to a new cellphone at a reduced cost.

1. Construct a 99% confidence interval estimate for the population proportion of subscribers that would upgrade to a new cellphone at a reduced cost.
2. How would the manager in charge of promotional programs use the results in (a)?

In a survey of 1,003 adults concerning complaints about restaurants, 732 complained about dirty or ill-equipped bathrooms and 381 complained about loud or distracting diners at other tables.

Source:Data extracted from "The Gripe-O-Meter Restaurants,"Consumer Reports, August 2014, p. 11.

1. Construct a 95% confidence interval estimate of the population proportion of adults who complained about dirty or ill-equipped bathrooms.
2. Construct a 95% confidence interval estimate of the population proportion of adults who complained about loud or distracting diners at other tables.
3. How would the manager of a chain of restaurants use the results of (a) and (b)?