8/29/2016

Discussion of Sampling Activity

Types of Variables

Questions about data

Graphical Displays

Stem and Leaf Plots

Histograms

Getting started with R

Graphical Displays with R (Use P:\data\math\stats\Datasets\ClassDataF16.csv)

In Class Exercises

  1. Construct appropriate graphs to visually summarize the information collected on the class data survey for the following variables: Gender, Year, height, wingspan, age, hair cut cost, handedness, coins, whitestring, blackstring, TV, pulse, and text messages.
  2. Is the shape of the distribution for guesses of the length of the black string the same as the distribution of guesses for the length of the white string?
  3. The actual length of the white sting is 46". Is the overall distribution of guesses centered at this value?
  4. The actual length of the black string is 48". Is the overall distribution of guesses centered at the appropriate value?
  5. Use appropriate graphical displays and descriptive statistics to make appropriate comparisons between men and women for different variables in the data set we collected during the first class.
  6. Use appropriate graphical displays and descriptive statistics to make appropriate comparisons between the four sections for different variables in the data set we collected during the first class.
  7. (Do this exercise "by hand," not with R.) Caution is necessary when constructing histograms from frequency distributions given in magazines, newspapers, journal articles, etc.  The authors of "Self-Reports of Academic Performance," an article which appeared in Soc. Methods and Research (1981), studied the difference in GPA, reported - actual, for each of the students in a sample.  Specify the height of each bar in a correct histogram for the frequency distribution below and sketch the histogram.

  Frequency distribution for errors in reported GPA

Class Interval Relative Frequency Height
[-2.0, -0.4)  .023
[-0.4, -0.2)  .055
[-0.2, -0.1)  .097
[-0.1,  0.0)  .210
[ 0.0,  0.1)  .189
[ 0.1,  0.2)  .139
[ 0.2,  0.4)  .116
[ 0.4,  2.0)  .171

Please read Section 1.3 for class on Wednesday