Do Now 12/5/12

Take out HW from last night.
– Punchline worksheets 107

Copy HW in your planner.
– Text p. 288, #1-3, 5-7, 9-11 all

Complete the Exploration activity on
“Populations and Samples”
Homework
Punchline worksheet 107
“Why Didn’t the Physics Teacher
Marry the Biology Teacher?”
THERE WAS NO CHEMISTRY
2)
1)
O.
E.
T.
H.
25
36
44
52
A.
I.
E.
C.
R.
83
77
92
35
50%
3)
4)
T. 64
E. 61
S. 65
Y. 62
R. 59
H. 63
N. 5
S. 71
W. 341
M. 13
Objective

SWBAT compare and analyze sampling
methods.
Section 7.3, “Populations and Samples”
When information is gathered
about a group, the entire group is
called a Population.
Sample
part of a population that is
representative of the whole population.
Types of Samples
For a random sample, members
of the population are chosen at random.
This gives every member of the population
an equal chance of being chosen.
A convenience sample is
based on members of the population that
are readily available.
Determine which sampling method will
better represent the entire population.
Justify your answer.
Sampling method
Maria surveys only the band students
she knows personally.
Jon writes each band student’s name
on a card. He questions those
students whose name he draws.
Results
84% want
blue uniforms
61% want
blue uniforms
Jon’s sample is a random sample, giving every band
member equal chance to be surveyed, so it is the
better method. Maria’s sample is a convenience
sample and therefore, could be biased.
Determine which sampling method will
better represent the entire population.
Justify your answer.
Sampling method
Ferdinand surveys every other
swimmer on the team.
Anna-Maria questions the swimmers
who are in her Biology class.
Results
72% want
practice early
50% want
practice early
Ferdinand’s sample is a random sample, giving
results that better represent the entire
swimming team, so it is the better method.
A biased sample is a sample
taken that does not fairly represent the
whole population.
A survey is given to 7th grade students who live in
Ocean county NJ regarding how many times a 7th
grade student living in the United States visits the
beach in the summer time.
Mickey Mouse takes a survey outside of the Magic
Kingdom regarding favorite places to vacation.
Determine whether each sample may be
biased. Explain.
The mayor surveys 100 supporters at a
rally about the most important issues to be
addressed by the city council.
The sample is biased. The supporters may have
different ideas than those not at the rally.
Determine whether each sample may be
biased. Explain.
The principal sends out questionnaires
to all of the students to find out what kind of
music students prefer at dances.
The sample is random. The students all have a chance
to respond.
Determine whether each sample may be
biased. Explain.
The owner of a record shop surveys only
customers over the age of 18 who shop at his
store.
The survey is biased and is not random.
Customers under the age of 18 do not have a
chance of being chosen.
Verifying Claims Based on
Statistical Data
A principal of a school with 1,500 students
estimates that about 400 students will attend a band
festival on Saturday. A random sample of 25 students
showed that 6 of them will attend. Determine
whether the principal’s estimate is likely to be
accurate.
Set up a proportion to predict the total number of students that will attend.
Students attending sample = Students attending
# of Students sampled
Student Population
6 = x
The estimate is not accurate
25
1500
because the data shows that 360
360 = x
students are likely to attend.
Verifying Claims Based on
Statistical Data
The owner of a large chain restaurant with 1,200 employees
estimates that about 250 employees will ask for winter
vacation. A random sample of 40 employees showed that 8
of them will ask for the time off. Determine whether the
owner’s estimate is likely to be accurate.
Set up a proportion to predict the total number of
employees asking for time off.
Employees surveyed for time off = Employees asking for time off
# of Employees surveyed
Total # of Employees
8 = x
40
1200
240 = x
The estimate is accurate because the
data shows that 240 employees will ask
for time off.
NJASK7 Prep
Homework
Text p. 288, #1-12 all, 17
Homework
Punchline worksheets 103 & 107
“What Do You Get When You Cross the
Atlantic with the Titanic?”
HALFWAY
“Why Didn’t the Physics Teacher
Marry the Biology Teacher?”
THERE WAS NO CHEMISTRY