A research study measured the sounds generated during eating tortilla chips. Peak loudness was measured (in decibels at 20 cm away) for both open-mouth and closed-mouth chewing. A sample size of 10 chips was used for each trial. For open-mouth chewing the mean peak loudness was 60 decibels with a standard deviation of 15 decibels. For closed-mouth chewing the mean peak loudness was 53 decibels with a standard deviation of 16 decibels. Is there evidence that there is a difference (open-closed) in mean peak loudness for open and closed mouth chewing of tortilla chips? (