LAB ACTIVITY 1

Due Monday, August 29, 2016 at 11:59pm

Welcome to the first “real” lab assignment of the semester! Remember that each lab assignment (including this one) will be worth 10 points. You’ll get to keep your best 12 lab assignment grades, so there are 120 points possible (out of 500 total) on all of your labs.

The primary goal of today’s lab is to introduce you to Minitab, the statistical software we will use for this class. Complete this worksheet—with a partner if you wish—and at the end you will be asked to submit your answers in ANGEL. Each student must turn in the lab individually, even if you teamed up during the lab class.

If you get stuck on anything, help is available! Check with the folks around you, and if you all have the same question then flag down the teaching assistant or the learning assistant.

1. Activity 1: Download data file and open Minitab.

a)One partner must log on to Angel and download the files for today’s lab (GPA.xlsx). This is found in the folder named “Datasets”. Remember where you save this file on your computer and open it in MS Excel.

b)Open Minitab following the menu sequence
Programs  Spreadsheets & Statistics  Minitab
Notice that Minitab starts up with three windows: Project, Session, and Worksheet (Project may be collapsed at the bottom of the screen).

Almost everything we will do in Minitab will be by selecting options from the drop-down menus along the top, i.e., ‘Data’, ‘Calc’, and so on. When you perform a command, such as creating a bar chart, for the first time, your lab activity may give you detailed instructions.

The top window, called Session, will contain the output from any work you do. The bottom window is a spreadsheet that will contain your data. Collapsed at the bottom is a window called Project. Project is Minitab’s top level of organization. You may only have one project open at a time and everything you are working with is stored there. If you save and re-open a project, you will find a complete record of all your work on the project. You should save your project regularly while working on it. Things can always go wrong, so save early and save often. Not shown here is a fourth type of window, called Graphics. This will appear when you ask Minitab to create a plot.

Activity 2: Getting data into Minitab

Now, let us examine a few ways to get data into Minitab.

  • The first is to simply enter them directly into the Spreadsheet. Enter the following data into Minitab:

Sex / Height(cm)
Female / 160
Female / 155
Male / 175
Male / 190

Notice that Minitab changed the label of the first column to C1-T, because it recognized that it now contains text data.

  • Another method is to copy and paste data from Excel. Go to your Excel window and copy the data from the first 11 rows, including the labels at the top (Sex, GPA, etc.) Highlight the first (unnumbered) row in the first column and paste the data from Excel. Note again, how Minitab recognized which columns contained text data.
  • Still another way to get data into Minitab is to import a spreadsheet. Use Open Worksheet, under the file menu, to open the file we downloaded at the beginning of lab.

What are the names of the variables in the GPA dataset?

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Activity 3: Plots with Minitab

Take another look at the menus at the top of the Minitab window. The File, Edit, Tools, Window, and Help menus are common to many programs and offer similar functions here in Minitab. The Stat and Graph menus contain statistical and graphing functions, respectively and are where you will do the majority of your work in this class.

Let’s start with some summaries of categorical variables, which we’ll learn more about in class tomorrow.

  • Create a pie chart of ‘Seat’: Graph  pie chart  chart counts of unique values  click in ‘categorical variable’ box  double click ‘Seat’ click ‘OK’

What is the largest category? ______

[As we discussed in class, please keep in mind that pie charts can be difficult to read and it’s generally better to use bar charts. However, the purpose of this lab is to explore the capabilities of Minitab.]

  • Create another pie chart, this time of the variable ‘Sex’. Before you click ‘Ok’, try adding percentages to your chart by selecting ‘Labels’  ‘slice labels’  Percent.

What is the percent of females in this data set? ______

  • Create a bar chart now to compare seating choices of Males and Females. To do this follow Graph  Bar chart  Cluster  OK  select ‘Sex’  select ‘seat’  OK

Briefly describe the differences in the two groups:

Activity 4: Descriptive Statistics with Minitab

Now, let’s try calculating some statistics.

  • Under the Stat menu, choose Basic Statistics and then Display Descriptive Statistics. Double click on GPA, MissClass, PartyDays, and StudyDays.

What kind of variables are these? A) Quantitative B) Categorical

  • Then click in the By variables box and select the variable ‘Sex’ to sort the data. Press OK.

What kind of variable is ‘Sex’? A) Quantitative B) Categorical

What is the mean number of StudyDays for Males? ______

To move your results into another program, such as Word, highlight the key parts of the session window and copy and paste the results into Word. If you want to copy the graph, select that window and then locate Copy Graph under the Edit menu.

If you want to print our results directly, select the desired window and then choose print from the file menu. Beware, that in the case of the session window, this will print the entire window.

Finally, save your work. You can save the individual components separately, but your best option is to save the entire project. Find this choice under the file menu.

That’s it! The last remaining step is to take the answers you entered in this worksheet and then transfer them into the ANGEL quiz. For this, you’ll need to login to ANGEL and look in the “Labs” folder for the “ANGEL lab activity” assessment.