Statistics 101 - Laboratory 1

Statistics 101 - Laboratory 1
The laboratory for this course has two functions. The first is to give you the opportunity to
experience and discuss statistics. This is done by way of a laboratory assignment that you will
complete in lab. The second is to provide you with a resource to help you better understand the
material in the course. The lab instructor is available to review difficult concepts from lecture
and/or provide assistance with homework (by working through similar problems on the board). In
laboratory, you are usually permitted to seek help from classmates or the lab instructor (although
this week’s math review/statistics pretest is an exception). Remember that you will be on your own
for exams so you should try to learn the material and not just ask for answers to the laboratory or
homework questions.
1. Group Exercise: Looking at Data - You may remember the tragic crash of the Challenger
space shuttle on January 27, 1986. The night before the crash there was a teleconference to
discuss whether to launch the shuttle the next day because the weather forecast called for cold
temperatures (30o F). It was thought that the cold temperature might affect the performance
of O-rings. The data in the figure below showing the temperature and number of O-ring
failures was an important part of the discussion. The engineers decided to launch; O-ring
failure was found to be the primary cause of the disaster. Discuss within your group the
questions below before writing down an answer for your group.
(a) Explain based on the figure above why the engineers decided cold temperatures were
not especially risky.
(b) It turns out that the data being examined omitted the 17 flights with no O-ring failures.
The figure on the next page gives the complete data for all 24 previous flights. Do you
think looking at the full data might have made a difference? Write a paragraph summarizing the relationship between the temperature and the likelihood that O-ring failures
2. Group Activity: Data Collection - The idea of variation is fundamental to the understanding of statistics. Your group will be doing basic research in biology. You are going to
measure the length of your left forearm. Humans have two bones in the forearm, the ulna
and the radius. To make sure everyone is measuring the same bone, we will all measure the
length of the left ulna. To do this, place your left forearm palm down on the table in front of
you. The ulna is the bone on the outside of your forearm. One end of the ulna is the larger
portion of the elbow; the bone closest to the table. The other end of the ulna is the small
bone on the outside of the left wrist. This bone sticks out a little bit for most people.
Take a tape measure and measure the distance between these two points. Make sure to
take this measurement in centimeters. On the group answer sheet, record the names and
measurements for every group member.
Once you have recorded these measurements on your answer sheet, please record your measurements on the board. Do not put names, just measurements.
After everyone has recorded their measurements, make a stem-and-leaf display of the measurements for the entire class. Describe what you see.
3. Individual Activity: Math Review/Statistics Pretest - Knowledge of high school
algebra is a prerequisite to this course. The questions on the Math Review are intended to
provide a refresher. Included in the Math Review is a Statistics pretest. You may be able to
answer these questions. If you do not know how to do some of the questions, you can leave
them black. You should answer the questions on your own. This part of the lab will be
corrected but you will not receive a grade. Pick up the Math Review from your lab
instructor when your group turns in answers to the group exercise.
Group Answer Sheet
Group Members:
1. Group Exercise: Looking at Data
2. Group Exercise: Data Collection
Length of Forearm (cm)
Stem and Leaf Plot
What do you see?