Descriptive Statistics

1 / 11

# Descriptive Statistics - PowerPoint PPT Presentation

Descriptive Statistics. Open the dataset ‘ ex02-01.mtp ’ using File  Open Worksheet . Data of breaking strength of wood (lbs). We will use Minitab’s descriptive statistics module to calculate the mean, standard deviation, interquartile range and the five-number summary .

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.

## PowerPoint Slideshow about 'Descriptive Statistics' - nelia

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
Descriptive Statistics
• Open the dataset ‘ex02-01.mtp’ using File Open Worksheet.
• Data of breaking strength of wood (lbs).
• We will use Minitab’s descriptive statistics module to calculate the mean, standard deviation, interquartile range and the five-number summary.
Descriptive Statistics
• First calculate the mean, std dev and IQR.

Select Stat

 Basic Statistics

 Display Descriptive Statistics

Select strength as the Variable.

Click on the Statistics button

Descriptive Statistics

Select Mean, Standard Deviation and Interquartile range

Make sure you unselect any of the other statistics

Click OK twice.

Descriptive Statistics: strength

Variable Mean StDev IQR

strength 30841 3019 2473

Five-Number Summary

From the menu bar select Stat

 Basic Statistics

 Display Descriptive Statistics

In the window, select strength as the variable

click the Statistics button

Five-Number Summary

Select First quartile

 Median

 Third quartile

 Min

 Max

click OK twice

Five-Number Summary

Descriptive Statistics: strength

Variable Minimum Q1 Median Q3 Maximum

strength 23040 30243 31975 32715 33650

Box Plot
• The box plot in Minitab is constructed in the standard way:
• The box is the interquartile range (IQR )
• 1st quartile is lower horizontal line and 3rd quartile is upper horizontal line
• The line in the middle of the box is the median (Q2 or 50th percentile).
• The whiskers represent 1.5 x IQR for the upper and lower.
• The IQR is a robust estimate of dispersion and is ~1.35.
• The asterisk (*) represents an outliervalue.
Box Plot
• Open the dataset ‘ex02-12.mtp’
• Data of counts of trees for different plots.
• A Box plot using theWith Groupsoption is used to examine the location and dispersion of a variable with several categories.
Box Plot

Select Graphs

 Boxplot from the menu bar.

In the Boxplots window select One Y, With Groups.

Click OK

Box Plot

Select trees for the Graph variable

Select group for the Categorical variable

click OK