For the "response" select the variable to be the "y" variable (predicted by the eauation) and for the "predictor" use your "x" variable (used to predict the response). Regression line and coefficient of determination (r-square): Use Stat>Regression>Regression. If you select more than two variables, you will geat a table giving the correlations between all pairs of variables. Select the variables for which you want the correlation. Listing the data in the session window is accomplished with the File>Display data command (select the column or columns you want displayed) - useful if you want a complete list of the values of one variable without printing the whole data window.Ĭorrelation coefficient (Pearson's r): Use Stat>Basic Statistics>Correlation. The row with the median is marked in parentheses.This is really a character graph - it shows up in the Session window - it's on the main graph menu because people use it a lot. In the display, an extra column at the left of the display shows the "depth" of the class - the distance (number of items) from the nearer end (large or small) of the data. You can set the increment at 5 to get a split stemplot. Select the variable(s) by double-clicking in the list at the left of the window. The resulting printout shows class midpoints (no class limits) and frequencies. The Interval is the class width (class interval, range for the class), the First midpoint is the class midpoint of the first class. Select the variable(s) by double-clicking in the list. Grouped frequency distribution : Use Graph>Character Graphs>Histogram. Q3 the third quartile - value separating the smallest three-quarters of the values from the rest Other descriptions Q1 the first quartile - value separating the smallest quarter of the values from the rest SEMean the standard error of the mean - the standard deviation divided by the square root of N StDev the standard deviation (s) of the values TrMean the 5% trimmed mean - the mean with the largest 5% and smallest 5% of the values deleted Mean the arithmetic mean (x-bar) of the values Median the "middle" value (half the values are at or above, half are at or below) Variable the name of the variable (unless you didn't name it - then you get the column number) With the cursor in the "Variables" box, select the columns you want described (highlight them and click on " Select " - or simply double-click on them) and click on OK (or press the Return/Enter key). Some descriptive statistics A: One-variable description Most complete description (pretty much all the one-variabledescription you need)įor the most commonly used descriptive measures, select Stat>Basic Statistics>Descriptive statistics. The lower the permeability value, the slower the pressure decay in the sandstone over time.Minitab: Descriptive Statistics Introduction to MINITAB in the Saint Mary's MicrocomputerLab V. Interpret the mode of the permeability measurements for Group C sandstone slices.Į. Interpret the mean and median of the permeability measurements for Group C sandstone slices.ĭ. Interpret the mean and median of the permeability measurements for Group B sandstone slices.Ĭ. Interpret the mean and median of the permeability measurements for Group A sandstone slices.ī. Measures of central tendency for the permeability measurements of each sandstone group are displayed in the accompanying Minitab printout.ĭescriptive Statistics: PermA, PermB, PermCĪ. The data for the study (simulated) are saved in the STONE file. These permeability values measure pressure decay as a function of time. All sandstone slices were then tested for permeability, measured in milliDarcies (mD). Slices in Group A were not exposed to any type of weathering slices in Group B were repeatedly sprayed with a 10% salt solution (to simulate wetting by driven rain) under temperate conditions and slices in Group C were soaked in a 10% salt solution and then dried (to simulate blocks of sandstone exposed during a wet winter and dried during a hot summer). Blocks of sandstone were cut into 300 equal-sized slices and the slices randomly divided into three groups of 100 slices each. An experiment was carried out to better understand the decay properties of sandstone when exposed to the weather ( Geographical Analysis, Vol. Natural stone, such as sandstone, is a popular building construction material. Permeability of sandstone during weathering.
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