A researcher wishes to draw a histogram in presenting graphical summaries of the data on the two main variables concerned - daily TV time in minutes and number of working hours, as stored in 'worktime'worksheet.

1. She decided to use 7 class intervals to construct a histogram for each variable. Explain how the researcher could have decided in using 7 as the number of class intervals to be used.
2. The researcher specified class intervals 0
3. Using Excel, draw and display the histogram for the working hours variable using the class intervals specified in part (b). Comment on the shape of the distribution of the data set as displayed in the histogram.
4. Using Excel, draw and display the histogram for the TV time variable using the class intervals specified in part (b). Comment on the shape of the distribution of the data set as displayed in the histogram.