You have probably got the field defined as a 'check box' in the table definition. If this field is actually destined for a form, then a check box may be appropriate. However, it can look odd in the table layout or on a report. If you want to change the display, simply look at the property box for the field on the table, form or report and change the display control from 'check box' to 'text'.

You may also like to think whether a Yes/No box really is the most appropriate data type to use. The user has to enter either 'Yes' or 'No' for the field. A 'Yes' (or tick in a check box) on a form for 'Smoker' may make sense, but seems (to me, at least) to be decidedly odd for the 'Sex' or 'member/class' fields for the Chelmer leisure Scenario (though it does save space). You may like to experiment with using a Look-Up Wizard for the data type here, and setting just the two values 'Male' and 'Female' or 'Member' and 'Class' for the list box that the Wizard will create. 'M' or 'F' etc would save space.