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Statdisk User Manual

Statdisk User Manual 13.0.0

for

STAT 3001

Table of Contents

Open a File …………………………..………………………………………………………………4

Edit Column Titles …………………………………………………………………………………..4

Copy a Dataset ………………………………………………………………………………………5

Paste a Dataset ………………………………………………………………………………………5

Sort a Dataset ………………………………………………………………………………………..6

Sample Transformations …………………………………………………………………………….6

Descriptive Statistics ………………………………………………………………………………..7

Creating a Histogram ……………………………………………………………………………….8

Creating Boxplots …………………………………………………………………………….….…9

Normal Distribution …………………………………………………….………………….…….…9

Confidence Intervals ……………………………………………………………………….………11

Hypothesis Testing ………………………………………………………………………….….…..12

Correlation and Regression ………………………………………………………………….….….13

Multiple Regression …………………………………………………………………….…….……14

Chi-Square Goodness-of-Fit …………………………………………………………………….…15

Chi-Square Test of Independence …………………………………………………………………18

One-Way Analysis of Variance ……………………………………………………………………19

When you open the Statdisk program you will see the screen shown in Figure 1. Be certain that you are using Version 13.0.0. Click on the OK button to close the Statdisk information screen.

Figure 1

You can perform all Statdisk functions from the Sample Editor Screen. The top of the screen has the following menus: File, Edit, Analysis, Data, Datasets, Window, and Help as shown in Figure 2.

Figure 2

Along with performing statistical calculations, Statdisk is also compatible with many popular software application packages. You can import, copy, paste, save, print and transform data sets. You can also copy, paste, save, or print any of the Statdisk numerical or graphical outputs and export them into other programs such as Microsoft Word. Those options are available as clickable buttons at the top of the Sample Editor screen as shown in Figure 3.

Figure 3

Opening a File

Statdisk has numerous datasets stored in the program and can be accessed by clicking on Datasets at the top of the Sample Editor window. After opening Datasets go to Elementary Statistics 13th Edition. The names of the datasets will appear to the right. Click on Body Data and the data values will appear in the Sample Editor as shown in figure 4.

Figure 4

You can preview the datasets quickly by opening a data set, review the data, and then select Clear to move in to the next file. You can also access datasets that Statdisk has available online by going to Help and then Triola Statistics Series.

Using Data Tools

After you have opened a dataset or have typed in data to the Sample Editor, you can edit column titles, sort data, delete columns, add columns or rows, or explore the data set by opening the Data Tools menu. The Data Tools button is located at the top of the Sample Editor page.

To Edit column titles open up Data Tools and then Edit column titles. Type in the names of the column titles into the box shown in Figure 5.

Figure 5

Click on the Save Changes button to enter the new column titles.

Copy and Paste

The Copy button is at the top of the Sample Editor Screen.

To copy columns from a data set simply click on the Copy button and a screen will appear asking you which column of data you want to copy (see figure 6). You can copy all of the columns or select columns. To Paste the column of data values into another column. Click on the column title (or number) then open the Edit menu and select Paste.

Figure 6

Sort Data

To sort data, select Data Tools and then select Sort Data. Use the drop-down arrow to select Sort One column, then select the column title and order from A to Z (see figure 7). Then click on Sort. The data values in that column will be sorted from lowest value to highest value.

Figure 7

The Data Menu

The two main menus in Statdisk are Analysis and Data.

The Data menu is used to sort data, add data, transform data, generate descriptive statistics including charts and graphs, assess normality and generate sets of data values that emulate one of the standard types of statistical distributions.

The Analysis menu is use to find area under the curve for many of the standard statistical distributions, determine sample size, create confidence intervals, perform hypothesis tests for parametric and non-parametric models.

Using the Data Menu

To transform a dataset you first need to type data into the sample editor or select an existing dataset. Open the Body Data file that was referenced in Opening a File earlier in the manual. Select Data and then Sample Transformations to open the Sample Transformer widow (see Figure 8). The Source column is the column containing the dataset that you want to transform. Select the operation that will be used to change the data values and type in the constant that you will add, subtract, multiply, divide, mod value, or raise to a power to the data values. After you click on Basic Transform the new data set will appear in the Sample Transformer window.

Figure 8

Descriptive Statistics

The descriptive statistics of a data set can be found by opening the Data menu and selecting Descriptive Statistics. Select the column that the data set is in and then click on Evaluate. A list of the most commonly used numerical descriptive statistics will be shown (see figure 9).

Figure 9

Histogram

A visual display of a single set of data values can be shown by opening the Data menu and then selecting Histogram.

Select the column that the data values are in. If you would like the Statdisk program to automatically select the class width and the class start, select Auto-fit. You can display the count or the frequency for each class by selecting Bar Labels. Click on Plot to display the graph (see figure 10).

Figure 10

You can also Print, Copy or Save the histogram and later paste the display in a Word file.

Boxplots

If you would like to compare two or more sets of data values you can plot them on one graph by using boxplots. Open the Data menu and select Boxplot. Then select the columns containing the data values that you would like to compare. You can then select Boxplot to show a standard view of the boxplots or Modified Boxplot which will emphasize outliers (see figure 11).

Figure 11

Using the Analysis Menu

Statdisk can perform many basic statistical functions relating to probability distributions, confidence intervals, hypothesis testing, correlation and regression, Chi-square and other non-parametric tests, and sample-size determination. This manual will explain how to perform many of those basic statistical functions.

Normal Distribution

You do not need to have a set of data values in the Sample Editor to use the probability distribution functions. Open the Analysis menu and select Probability Distributions. The first four functions, Normal Distribution, Student-t Distribution, Chi-Square Distribution, and the F Distribution perform the same type of tasks. Select Normal Distribution. The screen shown in Figure 12 will appear.

Figure 12

You can enter a Z value into the box to the right of z Value: or you can enter an amount of area to the left of some Z value under the standard normal distribution in the box to the right of Cumulative area from the left:. Figure 13 shows the standard normal distribution with Z-values along the bottom axis and the area under the curve between the given Z-values. Statdisk will find the given values and any other values that are not shown on the table.

Figure 13

Open the Analysis menu and then select Probability Distributions and then Normal Distribution. Enter -1 into the box for Z Value and then click on Evaluate. Figure 14 shows the Statdisk output.

Figure 14

The output gives the discrete probability of getting -1 or .2419707. It also gives the cumulative area to the left of -1 or .158655. If you add the areas to the left of -1 shown in Figure 13 you will get the same amount.

If you put in any value between 0 and 1 representing the area to the left of a Z score and then press Evaluate you will get the associated Z value.

Confidence Intervals

To find a confidence interval for a sample statistic you do not need to type in any data values or have a dataset in the Sample Editor. For example, to find a confidence interval for one-sample mean open up the Analysis menu then select Confidence Intervals and then Mean-One Sample. Figure 15 shows the Statdisk output screen for a 95% confidence interval with a sample mean of 26.7, a sample standard deviation of 4.1, and a sample size of 40. The confidence interval of 25.29 to 28.01 is given. The Margin of error is the distance from the mean to the upper value and the distance from the mean to the lower value of the confidence interval.