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Exercise 1
Austin Community College/BIO 1406 Laboratory Manual 12
th
Ed./Copyright 2006
11
EXERCISE 1
Name
How do scientists collect and analyze data?
Objectives
After completing this exercise, you should be able to:
♦
identify the names and functions of the laboratory items on display in the lab
♦
explain what a random variable is, and distinguish between discrete and continuous random variables
♦
use SI units when making measurements in lab
♦
convert between different SI units
♦
use the correct number of significant digits when reporting a measurement
♦
identify the number of significant digits in a reported measurement
♦
choose an appropriate measuring device when measuring distance, weight, or volume; and use it correctly
♦
use the correct number of significant digits when reporting computed values
♦
display data in a wellorganized and clearly labeled data table
♦
use a calculator to calculate the mean, percent error of the mean, and standard deviation of a list of
measurements; and explain what these statistics tell us
♦
use the appropriate statistics to compare the precision and accuracy of different measuring devices
♦
explain what the Student’s ttest is used for, and how to interpret the results
♦
use a spreadsheet program such as Excel to calculate the mean, percent error of the mean, and standard
deviation of list of measurements
♦
use a spreadsheet program such as Excel to carry out the Student’s ttest
Prelab
Before you come to lab, read this entire exercise.
You must also answer all questions
and complete all assignments on the first 14 pages of this exercise.
Your instructor will
give you directions on when and where to turn in your work.
Scientific investigation is based on
observations
.
Observations refer to any information we collect about the
physical universe using our senses (sight, sound, smell, taste, and touch.)
The factors or conditions being
observed are called
random variables
(or experimental variables) because our observations of them can
vary
from one trial to the next.
A random variable can be either
discrete
or
continuous
.
For example:
1.
A coin is tossed ten times. The random variable X is defined as the number of tails that occur.
Because
X can only take certain values (0, 1, 2, 3, 4, ….10) it is a
discrete random variable
.
2.
The length of a sheet of paper is measured. The random variable Y is defined as its length in
centimeters. Because Y can take any positive real value, it is a
continuous random variable
.
Your Turn
Give an example of a discrete random variable:
_____________________________________________
____________________________________________________________________________________
Give an example of a continuous random variable:
___________________________________________
____________________________________________________________________________________
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View Full DocumentExercise 1
Austin Community College/BIO 1406 Laboratory Manual 12
th
Ed./Copyright 2006
12
A major advance in science occurred when scientists realized the advantage of describing observations of
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 Summer '09
 BOSTIC
 molecular biology

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