MINITAB III

• Data can be entered horizontally or vertically (as Rows or Columns).In the top left corner of the Worksheet window, there is a cell with an arrow in it.  Click this cell to change the action of the Enter key. 

• Pointing down arrow  then the cursor will go down the column when you press Enter.  

• Arrow pointing to the right( →) - then the cursor will go across the row, to the next column when you press Enter. 

Consider the following collection of data

Temperature(C)	Water consumption (ml)
15	470
17	500
19	540
21	550
23	620
25	680
27	740

i

Calculating

Using calculator

• If the data in columns are to be changed before calculating statistical values that can be done using calculator. Ex: calculate store temperature in Fahrenheit or volume in another scale
• Open calculator using menu Calc and selecting option Calculator

In this calcaultor on left hand side the columns and constants are dispalyed.

• Store result in variable: If a single value is calculated it can be stored in a constant or in a column. For multiple values a column must be used.
• Expression: the expression can be built in this text box. For that numbers ,simbols and functions can be used. To obtain results have to click on Ok button. 

Save

• Minitab has facilitated to save the data as the entire project or the worksheet. Saving the worksheet as a separate file is a good practice.
• By using File menu and options Save Project/ Save Current Worksheet data can be saved in a storage device.

Statistical Analysis

Minitab is a software that can be used to calculate many statistical details based on a collection of data. Under the menu Stat there are number of options relates with statistic experiments, these options vary on software version.

For the above collection of data

Find the mean and standard deviation for the temperature/water data,

1. Select  Stat > Basic Statistics > Display Descriptive Statistics
2. In the Variables box, select C1 (Temperature).
3. Click OK.

Definitions of the terms in the output

1. N = number of data items in the sample 
2. N* = number of items in the sample that have missing values (N* does not show up when all the items in the sample have values) 
3. Mean = average 
4. Median = 50^th percentile 
5. TrMean= the 5% trimmed mean 
6. StDev = standard deviation 
7. SE Mean = standard error of the mean (standard deviation divided by the square root of the sample size) 
8. Minimum = smallest data value 
9. Maximum = largest data value 
10. Q1 = 25^th percentile = first quartile 
11. Q3 = 75^th percentile = third quartile

Graphs

1. To draw a histogram, select Graph > Histogram.
2. In the Graph Variables box, select C1 (Temperature).
3. Click Ok.  

Note: You can change the settings for the width of the bars  in the histogram by clicking Options  on the histogram dialog box and making the desired changes.)

1. 
   To draw a boxplot, select Graph > Boxplot.
2. In the Graph Variables box under the
    Y select C1 (Temperature).
    The X column is for categories.  
3. Click Ok. 

1. To graph a scatterplot for the water consumption based on the temperature,
    select Graph > Scatter Plot.
2. In the Graph Variables box,
   under the Y, select C2 (Water Consumption)
    and under the X, select C1 (Temperature).
3. Click Ok

To save graphs the entire project has to be saved using Save Project As or Save Project options

Exercise

Reg No	Subject 1	Subject 2	Subject 3	Subject 4
PS/0899/002	78	82	85	76
IS/0999/003	56	58	54	69
LS/090/004	25	50	45	35
MS/009/005	89	92	89	87
OS/099/008	68	72	89	78
WS/079/010	50	58	79	54
QS/089/012	45	68	46	58

1.       Enter the data in above table to the worksheet.

2.       Change the marks of subject 1 by adding 5 marks using calculator.

3.       Find Row and column statistics by customizing the selections available.

4.       Find Descriptive statistics using Basic statistics menu on these data based on subjects.

5.        Generate graphs using Graph menu based on subjects.