The most popular visualisation tools for detecting outliers are scatter plots and box plots. Scatter plots — Scatter plots can be used to specifically find outliers in a dataset or a specific attribute.
Go to the Home tab after opening the sheet and selecting the cells you want to format. Click the Conditional Formatting drop-down arrow in the Styles section of the ribbon. Choose "A Date Occurring" from the pop-out menu when you move your cursor to Highlight Cell Rules. You'll see a little window pop up where you may put up your rule.
Microsoft Excel gives you ten options for formatting cells based on the current date. Simply go to the Home tab > Conditional Formatting > Highlight Cell Rules and pick A Date Occurring to apply the formatting.
A value in a set of data that "lies outside" (is substantially smaller or greater than) the majority of the other values. For example, both 3 and 85 are "outliers" among the scores 25,29,3,32,85,33,27,28.