The lecturer wishes to draw histograms in presenting graphical summaries of the data on the two main variables concerned - weekly working hours and marks attained, as stored in 'HoursMark55' worksheet.

(a)She decided to use 7 class intervals to construct a histogram for each variable. Explain how the lecturer could have decided in using 7 as the number of class intervals to be used. 1 mark

(b)The lecturer specified class intervals 0

(c)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. marks

Using Excel, draw and display the histogram for the marks attained 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.

this is the excel spreedsheet image