1. 1: Analyzing Categorical Data
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- Navigate this page:
- 1.3: Describing Quantitative Data with Numbers EXAMPLE How many pets
- Mean and Median Applet
- Steps to find the standard deviation
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See if you can match the image on the right. 
Using Histograms Wisely Here are several cautions based on common mistakes students make when using histograms. Cautions! Don’t confuse histograms and bar graphs. The bars must be touching on a histogram Histograms show quantitative variables while bar graphs shows categorical variables Don’t use counts (in a frequency table) or percents (in a relative frequency table) as data. The data refers to the x-axis Use percents instead of counts on the vertical axis when comparing distributions with different numbers of observations. Just because a graph looks nice, it’s not necessarily a meaningful display of data. Be sure to choose classes that are all the same width Have at least about five classes Ex: About 1.6 million first-year students enroll in colleges and universities each year. What do they plan to study? The graph on the right displays data on the percents of first-year students who plan to major in several discipline areas. 
Is this a bar graph or a histogram? Explain. Would it be correct to describe this distribution as right-skewed? Why or why not?  1.3: Describing Quantitative Data with Numbers
EXAMPLE How many pets? A group of elementary school children was asked how many pets they have. Here are their responses, arranged from lowest to highest: 1 3 4 4 4 5 7 8 9 How can we describe the center of this data set? Measures of center (central tendency) Median Mean Mode? Note: Population mean vs. sample mean Mean and Median Applet: http://digitalfirst.bfwpub.com/stats_applet/stats_applet_6_meanmed.html 
Ex: People say that it takes a long time to get to work in New York State due to the heavy traffic near big cities. What do the data say? The stemplot shows the travel times in minutes of 20 randomly chosen New York workers. How would you summarize the center of the distribution? 
Measure of spread/variability Range By looking at deviations from the mean Mean absolute deviation (MAD) Variance Standard deviation Steps to find the standard deviation: 
Calculate the mean. Calculate each deviation. deviation = observation – mean 
Square each deviation. Find the sum of the squared deviations. Divide the sum by n – 1 (basically finding the “average” squared deviation)…this is called the Directory: ourpages -> auto -> 2017 2017 -> Senior Division Solutions 2017 -> Avant garde adademy of broward 2017 -> Have you always wanted to go to space camp? Dreamt of becoming an astronaut here’s your chance! 2017 -> Atlanta, georgia-april 2017-a total solar eclipse occurs when the moon lines up between the earth and the sun-an extremely rare and beautiful event 2017 -> United states history and geography unit 1: The Rise of Industrial America 1877-1914 2017 -> Out-of-Field Notification to Parents/Guardians English 2017 -> Modern History Notes 9-21-2017 Entertainment 2017 -> The secret of change is to focus all of your energy, not on fighting the old, but on building the new 2017 -> The Berlin Conference 1884 Simulation Historical Context 2017 -> Island Biogeography and Biodiversity Part I: Background Reading Download 10.83 Mb. Share with your friends:
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