In this lab we will use the data that were collected in class to answer a few questions.  In doing so we will learn how to get a data set into Minitab, how to display and summarize categorical and quantitative data, we will also look at a relationship between two variables.  

Click here to find the "Statistics Class Survey" data set.  Select all of the data set, copy it, and paste it into a Minitab worksheet.  When you paste the document, make sure you have your cursor in the upper left gray cell---not in row 1.  Using the data set, answer the following questions.
 
For data from Fall '08 download the Minitab worksheet here.

1. Graphing Data.  In this first question, you are going to make three graphs.  After you make each graph, copy and paste it into Word. (To copy each graph right-click the mouse in the graph window and select copy graph. To paste it into Word use Edit > Paste Special > Bitmap)

1. A common graph used for a single quantitative variable is a histogram.  Make a histogram of one of the quantitative variables in the data set.  To do this click on Graph > Histogram,  click OK in the first window that pops up, in the second window double click on the variable you want to graph and click OK.
2. When comparing two different quantitative variables graphically, side-by-side boxplots can be used.  Make side-by-side boxplots of your quantitative variable with males in one boxplot and females in the other.  To do this click on Graph > Boxplot > With Groups.  Put your quantitative variable in the variables box and Gender in the Categorical Variables box.
   
3. A common graph used for categorical variables is a pie chart.  Make a pie chart from one of the categorical variables.  To do this click on Graph > Pie Chart make sure Chart raw data is chosen and in Categorical variable: put the variable you want to graph.
4. To graph a relationship between two quantitative variables, a scatterplot is used.  Make a scatterplot to look at the relationship between two quantitative variables.  To do this click on Graph > Scatterplot. With the Simple scatterplot highlighted in the first pop-up window click OK.  Put one of your variables in as the Y-Variable and the other as the X-Variable and click OK.

2. Describing Data.  In this question, we calculate numbers that will help describe the data that were graphed in the first question.  Put these numbers into Word as answers to question 2.  Write your answers as complete sentences.
   

1. Mean and median are the two most common measures of center for quantitative data.  Find the mean and median for the quantitative variable you graphed in question 1a.  To do this click on Stat > Basic Statistics > Display Descriptive Statistics.  Put your quantitative variable in the Variables box and click OK.
   
2. Using your quantitative variable, find the mean and median for just the females and the mean and median for just the males.  To do this click on Stat > Basic Statistics > Display Descriptive Statistics.  Add gender to the By Variables box.
   
3. Proportions or percents are a way to summarize categorical variables.  Find the percents for your categorical variable from question 1c.  To do this click on Stat  > Tables > Tally Individual Variables.  Put your categorical variable in the variables box, click on Percent and OK.
4. Correlation is used to measure the strength and direction of a linear relationship between two quantitative variables.  Find the correlation between your two quantitative variables from question 1.  To do this click on Stat > Basic Statistics > Correlation.  Put your two variables in the variables box and click OK.