Statistics homework help

Statistics homework help. Problem Set #1
Due Week 3, Wednesday 10 PM EST
Exercise 1.1: Classifying Variables
For each of the following variables:
Tell whether the variable is quantitative or categorical, identify the observational units, if the variable is quantitative, tell whether it is continuous or discrete.
 

  1. The month a person is born
  2. The amount of money a person has on his/her person
  3. The color of an M&M candy taken from a bag
  4. The number of grams of fat in a cookie
  5. The amount of time a car waits at the drive-through of a fast food restaurant
  6. The number of M&M candies in a 10 oz. bag

 
 
Exercise 1.2: Years In Town
A class of students recorded the number of years their families had lived in their town. Here are two graphs that students drew to summarize the data.
 
 
 

  1. What is the variable(s)? Is it (Are they) categorical or quantitative?
  2. Which graph gives a more accurate representation of the data? Why?
  3. Create a frequency table and a relative frequency table for this data.

 
 
 
 
 
Exercise 1.3: Exam Scores
Adapted from Allan J. Rossman, Beth L. Chance, and Robin H. Lock, Workshop Statistics: Discovery with Data and Fathom (Key College Publishing, 2001), 265 – 277
 
Nine hypothetical classes (A, B, C, D, E, F, G, H, I) were given the same exam. The comparative dot plots below show the distributions of the exam scores for each class.
 

  1. PLOT 1: Compare the distributions for the exam scores for classes A, B, and C. What is the most distinctive difference among the three distributions? How would you interpret this difference in this context?

 
 

  1. PLOT 2: Compare the distributions for the exam scores for classes D, E, and C. What is the most distinctive difference among the three distributions? How would you interpret this difference in this context?

 
 

  1. PLOT 3: Compare the distributions for the exam scores for classes G, H, and I. What is the most distinctive difference among the three distributions? How would you interpret this difference in this context?

 
 
 
 
Exercise 1.4: Children’s Television Viewing
Adapted from Allan J. Rossman, Beth L. Chance, and Robin H. Lock, Workshop Statistics: Discovery with Data and Fathom (Key College Publishing, 2001), 16, 310
 
Researchers at Stanford studied whether reducing children’s television viewing might help to prevent obesity. Third and fourth graders at two public elementary schools in San Jose were the subjects. One of the schools incorporated a curriculum designed to reduce watching television and playing video games, while the other school made no changes to its curriculum. At the beginning and end of the study a variety of variables were measured on each child. These included body mass index, tricep skinfold thickness, waist circumference, waist-to-hip ratio, weekly time spent watching television, and weekly time spent playing video games. The researchers found significant decreases in these variables for the students at the school with the special curriculum.

  1. Is this study observational or experimental? Explain. If experimental, what is the control group and what is the treatment group?
  2. Is the sampling method random? Explain.
  3. Identify at least one lurking variable for this study. Explain why it is a lurking variable.

 
 
Exercise 1.5: Placement Exam Scores
Adapted from Allan J. Rossman, Beth L. Chance, and Robin H. Lock, Workshop Statistics: Discovery with Data and Fathom (Key College Publishing, 2001), 59
The Department of Mathematics and Computer Science at Dickinson College gives an exam each fall to freshman who intend to take calculus. The scores on the exam are used to determine into which level of calculus a student should be placed. The exam consists of 20 multiple-choice questions. Scores for the 213 students who took the exam in 1992 are found in the Excel File, MathPlacementScores.xls.
 

  1. What is/are the variable(s)? Classify as categorical or quantitative.
  2. This is the dot plot of this distribution. List at least two conclusions you make from this display.

 

  1. Create a histogram you feel best summarizes the distribution. Justify your choice. This applet may be useful: http://people.hofstra.edu/Stefan_Waner/RealWorld/stats/histogram.html

You may also make a Histogram in Excel, or by hand.
Take a screen shot or picture of your histogram and include it in your answers.
 

  1. Give an interval of “typical” scores for this group. Briefly describe why you chose this interval (why you believe it is typical). Include your estimate of the probability that a student would score in this interval, and explain why you feel it is a good estimate.

 
Exercise 1.6: DoW #3 Collection Tool
In weeks 1 and 2 of this course, you worked with your group to design and implement a data collection tool for DoW #3, comparing the number of raisins in a box for two different brands of raisins.

  1. Summarize the method your group used to collect the data. Provide rationale for decisions your group made.

 

  1. Evaluate the effectiveness of your tool. Do you think your tool collected quality data? Why or why not? (Be sure to discuss possible sources of bias in your response to this question)

 

Statistics homework help