Download Multiple Bar Charts - Buisness Management - Lecture Notes and more Study notes Business Administration in PDF only on Docsity! Multiple Bar Charts The data below gives the daily sales of CDs (in £) by music type for an independent retailer. Day Chart Dance Rest Total Monday 12000 10000 2700 24700 Tuesday 11000 8000 3000 22000 Wednesday 9000 6000 2000 17000 Thursday 10000 5000 2500 17500 Friday 12000 11000 3000 26000 Saturday 19000 12000 4000 35000 Sunday 10000 8000 2000 20000 Total 83000 60000 19200 162200 Bar charts could be drawn of total sales per music type in the week, or of total daily sales. It might be interesting to see daily sales broken down into music types. This can be done in a similar manner to the bar charts produced previously. The only difference is that the height of the bars is dictated by the total daily sales, and each bar has segments representing each music type. This is done inMINITAB as follows: 22 Docsity.com 1. Enter the data into the worksheet, the types of music in columns and the days as rows. 2. Graph > Bar Chart... 3. Select the appropriate data format and the Stack graph format. 4. Click OK 5. Enter the column containing the Sales data under Graph variables and the Day and Music Type in the grouping dialogue box 6. Click OK. 23 Docsity.com Normally, as with stem and leaf plots and bar charts we would getMINITAB to do this for us. 1. Enter the data in column C1 of the worksheet. For illustrative purposes I have randomly generated 500 observations in this column. 2. Graph > Histogram... 3. Select the Simple graph format 4. Select C1 under Graph variables. Note: various advanced options are available e.g. a title can be added by clicking Labels 5. When happy with your choices click OK. 26 Docsity.com These instructions produce the following histogram: The histogram produced can be amended by right-clicking on the graph. For example, the intervals used in the histogram can be changed or, more simply, the number of intervals using Edit bars > Binning We can double the number of intervals (from 18 to 36 intervals) using the Binning dialogue box 27 Docsity.com This changes the histogram to Histograms are useful tools in data analysis. They are easy to produce inMINITAB for large data sets and provide a clear visual representation of the data. Using histograms, it is easy to spot the modal or most popular class in the data, the one with the highest peak. It is also easy to spot simple patterns in the data. Is the frequency distribution symmetric, as the histograms produced above, or is it skewed to one side like the left-hand histogram in the following graphic. Histograms also allow us to make early judgements as to whether all our data come from the same population. Consider the right-hand histogram in the graphic below. It clearly contains two separate modes (peaks), each of which has its own symmetric pattern of data. This clearly suggests that the data come from two separate populations, one centred around 85 with a narrow spread and one centred around 100 with a wider spread. In real situations it is unlikely that the difference would be as dramatic, unless you had a poor sampling method. However the drawing of histograms is often the firs stage of more complex analysis. 28 Docsity.com
