Tom Frederick is the computer support manager for a large company whose employees have been complaining about spam, which many of us know as unwanted

Tom Frederick is the computer support manager for a large company whose employees have been complaining about €œspam,€ which many of us know as unwanted e-mail to solicit our money or our attention. Tom asked a sample of 9 employees to keep track of the number of spam messages they received during the previous week. He then installed a spam €œfilter€ into the e-mail system to block some of the spam by identifying key words that often appear in such messages. During the week following installation of the filter, the number of spam messages received by each of the 9 employees was again counted, with the results shown here. At the 0.05 level of significance, can we conclude that Tom€™s filtering system is effective in reducing the weekly number of spam messages an employee receives?

Employee: Spam Messages Before Filter 28 27 24 18 23 28 25 20 28 Spam Messages After Filter 19 25 25 19 20 21 18 21 22