Before deeming a substance suitable for landfilling, it is essential to characterize its chemical properties. The article 'Landfilling Ash/Sludges Mixtures discusses the chemical properties of sludge from a wastewater treatment plant in New Hampshire. In a sample of six replicates, the researchers found that the mean pH was 6.68, with a standard deviation of 0.20. Can we conclude that the average pH of this space exploration-related substance is less than 7.0?