Download Systematic - Mrs-Cook-8th-Grade-Math

Bell Ringer
3-28-11 1
1
1
2 cups of milk, 2 4
A recipe for 12 waffles calls for
cups of flour, and 1 1 cups of other ingredients.
3
1. How many cups of milk, flour, and other
ingredients are needed to make 36 waffles?
2. If the recipe is doubled, how many cups of milk,
flour, and other ingredients are needed?
3. Mr. Loya stated that the circumference of Earth
at the equator is 24,902.4 miles. Write the
expression that represents this number in
scientific notation?
A recipe for 12 waffles calls for 1 12 cups of milk, 2 14
1
1
cups of flour, and 3 cups of other ingredients.
1. How many cups of milk, flour, and other
ingredients are needed to make 36 waffles?
1
1 1
1  2 1
2
4 3
3 9 4
 
2 4 3
18 27 16 61

 
12 12 12 12
61 3 183
1
 
 15 cups
12 1 12
4
2. If the recipe is doubled, how many cups of milk,
flour, and other ingredients are needed?
18 27 16 61

 
12 12 12 12
61 2 122
1
 
 10 cups
12 1 12
6
3. Mr. Loya stated that the circumference of Earth
at the equator is 24,902.4 miles. Write the
expression that represents this number in
scientific notation?
24,902.4
 1 : PositiveExponent
1stFactor : Between1&10
2.49024  10 miles
4
Quiz
3-28-11
The students in Mr. Lee’s science class are
ordering materials they will need for a science
experiment. Each student will need a bag of
plant seeds that costs $1.00 and a 6-plant tray
that costs $3.50. If x represents the number
of students in Mr. Lee’s science class, which
equation can be used to find y, the amount in
dollars spent by Mr. Lee’s students?
A.
B.
C.
D.
y = 3.5x + 1
y = 4.5x
y = x + 4.5
y = x + 3.5
The students in Mr. Lee’s science class are ordering materials they will need for a
science experiment. Each student will need a bag of plant seeds that costs $1.00 and a
6-plant tray that costs $3.50. If x represents the number of students in Mr. Lee’s science
class, which equation can be used to find y, the amount in dollars spent by Mr. Lee’s
students?
Which equation can be
used?
EachStudent : $1  3.5  $4.50
Total Cost :
Student cost (total students)
Total  4.5(# students)
EquationB
Seeds = $1.00/student
Plant tray = $3.50/student
x = # students
y = Total money needed
Since each student needs $1 for the seeds
and $3.50 for the tray, I added the two
amounts together. Each student needs
$4.50. To find the total cost, you would
multiply the cost per student by the number
of students.
Equation B can be used to find the
total cost.
Speed Test
1. Get out a dry erase marker.
2. You have 1 minute to complete as
many problems as you can.
3.We will grade in 1 minute.
4. Graph your results. Keep the graph in
your notebook.
5. We will do this every day.
Problem of the Week
#5-3
1. You have 5 minutes to work on the
problem of the week and word problem.
2. The problem of the week must follow
the Read, Think, Solve, Justify format.
3. When you are finished, turn them in.
4. They are due Friday.
Reach for the Stars
Monday
A right triangle with leg lengths of 6 and 8 inches
is dilated by a scale factor of 3.5 to produce a
new right triangle. What is the perimeter of the
new triangle?
A.
B.
C.
D.
49 in
24 in
84 in
59 in
Reach for the Stars
Monday
The Sundown Parking Garage charges $5.00 to park
a car for the first hour and $0.75 for each
additional hour or part of an hour after the first
hour. What is the total charge for parking a car
for 4 hours 42 minutes in this garage?
A.
B.
C.
D.
$5.75
$6.50
$7.25
$8.00
Reach for the Stars
Monday
Which table best represents the equation
shown below?
y = 2x + 3
Class Work:
Sampling
You need your notes. Title the notes:
Sampling
I will check your work at the end of
class.
Survey
• Survey – collection of factual data or
opinions
• Population – group from which you
want to gain information.
• Sample – part of the population you
survey
• Random sample – members surveyed
are not predetermined
Survey
You want to know the favorite food
of GMS 8th grade students. You
take a survey of the students in
your math class.
1. Identify the population
GMS 8th grade students
2. Identify the sample
Students in math class
Sampling Methods
• Convenience – members of the
population are selected because they
are available.
– 4th period Math students
– Students in the hall
• Systematic – members of the
population are selected according to a
pattern.
– Every 5th person walking in the hall
Sampling Methods
Convenience?
1. Determining the favorite candidate for
8th grade president by asking every 10th
student entering the auditorium.
Convenience
2. Determining the most popular type of
motorcycle by calling people listed on the
100th page of the phone book.
Not Convenient
3. Determining the favorite store by asking
everyone who enters the mall.
Convenience
Sampling Methods
Systematic?
1. Sending a questionnaire to students at
a track meet?
Not Systematic
2. Sending a questionnaire to every 9th
person that enters a room?
Systematic
3. Determining the favorite color by
asking every 5th person standing in the
lunch line.
Systematic
Sampling Methods
Biased –the sample is not random
because the results may not
represent the whole population.
Asking customers of Wal-Mart what their
favorite store is
Asking football players what their favorite
sport is
Sampling Methods
Biased?
1. Asking Brookshire’s customers what
their favorite grocery store is?
Biased
2. Asking an 8th grade class what their
favorite sport is? Not Biased
3. Asking people at Six Flags if they like
amusement parks.
Biased
You want to know the favorite sport of middle
school students. You ask every 8th person
that enters the football game at GMS.
1. Identify the population
Middle School students
2. Identify the sample
People at GMS football game
3. Identify the sampling method.
Systematic
4. Is the survey biased?
Yes: Asking at a football game
5. Is the sample representative of the population?
No: Other people besides middle school
students may be at the football game.
Class Work
TAKS Coach
Pg. 244 – 245: 1-5
**Remember to
Justify ALL Answers**
TAKS
Monday
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