Math221 Statistical Concepts week 2

Statistics – Lab Week 2

Name:_______________________

Math221

Statistical Concepts:

· Using Minitab

· Graphics

· Shapes of Distributions

· Descriptive Statistics

· Empirical Rule

Ø Minitab is a powerful, yet user-friendly, data analysis software package. You can launch Minitab by finding the icon and double clicking on it. After a moment you will see two windows, the Session Window in the top half of the screen and the Worksheet or Data Window in the bottom half.

Ø Data have already been formatted and entered into a Minitab worksheet. Go to the eCollege Doc sharing site to download this data file. The names of each variable from the survey are in the first row of the Worksheet. This row has a background color of gray to identify it as the variable names. All other rows of the Minitab Worksheet represent a certain students’ answers to the survey questions. Therefore, the rows are called observations and the columns are called variables. Included with this lab, you will find a code sheet that identifies the correspondence between the variable names and the survey questions.

Ø Complete the questions after the Code Sheet and paste the Graphs from Minitab in the grey areas for question 1 through 3. Type your answers to questions 4 through 11 where noted in the grey areas. When asked for explanations, please give thorough, multi-sentence or paragraph length explanations. The completed iLab Word Document with your responses to the questions will be the ONE and only document submitted to the dropbox. When saving and submitting the document, you are required to use the following format: Last Name_ First Name_Week2iLab.

Code Sheet

Do NOT answer these questions. The Code Sheet just lists the variables name and the question used by the researchers on the survey instrument that produced the data that are included in the Minitab data file. This is just information. The first question for the lab is after the code sheet.

Creating Graphs

1. Create a Pie Chart for the variable Car - Pull up Graph > Pie Chart and click in the categories variables box so that the list of variables will show up on the left. Now double click on the variable name 'Car" in the box at the left of the window. Include a title by clicking on the "Labels." button and typing it in the correct text area (put your name in as the title). In this same labels window, select the tab- Slice Labels and click on all; Category name; Frequency; Percent; Draw a line from label to slice and then click OK. Click OK again to create graph. Click on the graph and use Ctrl+C to copy and come back here, click below this question and use Ctrl+V to paste it in this Word document.

2. Create a histogram for the variable Height – Pull up Graph > Histograms and choose “Simple”. Then set the graph variable to “height”. Include a title by clicking on the “Labels…” button and typing it in the correct text area (put your name in as the title) and click OK. Copy and paste the graph here.

3.Create a stem and leaf chart for the variable Money – Pull up Graph > Stem-and Leaf and set Variables: to “Money”. Enter 10 for theIncrement: and click OK.
The leaves of the stem-leaf plot will be the one’s digits of the values in the “Money” variable. Note: the first column of the stem-leaf plot that you create is the count. The row with the count in parentheses includes the median. The counts below the median cumulate from the bottom of the plot.
Copy and paste the graph here.

4. Calculate descriptive statistics for the variable Height by Gender – Pull up Stat > Basic Statistics > Display Descriptive Statistics and setVariables: to Height. Check By variable: and enter Gender into this text box. Click OK. Type the mean and the standard deviation for both males and females in the space below this question.

Ø Select File > Save Worksheet As to save the data set. You must either keep a copy of this data or download it again off the web site for future labs.

Short Answer Writing Assignment

All answers should be complete sentences.

5. What is the most common color of car for students who participated in this survey? Explain how you arrived at your answer.

1. What is seen in the histogram created for the heights of students in this class (include the shape)? Explain your answer.

1. What is seen in the stem and leaf plot for the money variable (include the shape)? Explain your answer.

1. Compare the mean for the heights of males and the mean for the heights of females in these data. Compare the values and explain what can be concluded based on the numbers.

1. Compare the standard deviation for the heights of males and the standard deviation for the heights of females in the class. Compare the values and explain what can be concluded based on the numbers.

1. Using the empirical rule, 95% of female heights should be between what two values? Either show work or explain how your answer was calculated.

1. Using the empirical rule, 68% of male heights should be between what two values? Either show work or explain how your answer was calculated.