Informal Geometry Period 1

1
Warm Up

• Your parents are letting you take 3 friends on a
  trip with you. You have 10 friends that you are
  considering to take with you. How many
  possibilities do you have?
• 2) You are playing a game with your friend. They
  will give you 10 dollars if you get doubles when
  rolling two dice. You have to pay them 2 if you
  get anything else. What is the expected value of
  this game? Is it a fair game?

120
0, yes
2
EOCT Practice
A spinner has 3 sections, each with different
point values and areas. - The 1-point section is
2/3 of the area of the spinner. - The 2-point
section is1/4 of the area of the spinner. - The
3-point section is 1/12 of the area of the
spinner. To the nearest tenth of a point, what
is the expected value?

• 0.7
• 1.4
• 2.0
• 6.0

b
3
EOCT Practice
Greg wrote the numbers 1 through 9 on pieces of
paper and placed them in a hat. He will randomly
select one piece of paper from the hat. He will
not replace it. Greg will then randomly select a
second piece of paper from the hat. What is the
probability that Greg will select a piece of
paper with an odd number on it and then, select
one with an even number on it?

• 20/81
• 5/18
• 9/17
• 19/18

b
4
Benchmark 2-13
Which is equivalent to ?

• b)
• c)
• d)

c
5
Benchmark 2-14

• y3x3
• yx26
• yx2-7
• yx33

c
6
Benchmark 2-15
Calculate the sum of the interior angles of the
figure below.
c
a) 180 b) 540 c) 360 d) 720
7
Quiz Review
8
Math IDay 55 (10-28-09)
UNIT QUESTION How do you use probability to make
plans and predict for the future? Standard
MM1D1-3 Todays Question How do we take a
random sample, and what statistics can we find
with the data? Standard MM1D3.a.
9
Random Sampling

• John surveys every fifth person leaving a pet
  supply store. Of those surveyed, ¾ support the
  city managers proposition to tear down the old
  library and replace the area with the
  construction of a new pet park. John plans to
  write a letter to the editor of the local
  newspaper about the proposal for the new pet park
  stating that there is tremendous support from the
  citizens of the town for constructing a new pet
  park.
• Can the conclusion John stated be accurately
  supported?
• b) Suggest another plan for obtaining a good
  sample population.

10
Random Sampling
I want to know the average height of students at
Hillgrove High School. What would be a good
method to find this number without checking every
student?
11
Random Sampling

• Sample Problem 1
• Your school is conducting a survey on a proposed
  dress code. The first 20 students entering the
  school in the morning are surveyed. What type of
  sampling method is used?
• Convenience
• Random
• Stratified random
• Systematic

12
Random Sampling

• Sample Problem 2
• A principal is surveying the parents of his
  school to find out if they support extending the
  school day by 20 minutes. Which of the following
  methods of choosing a sample will most likely
  result in a sample that is representative of all
  parents?
• Surveying all the parents at a parent teacher
  meeting
• Surveying 50 parents of 9th grade students
• Surveying all the parents who volunteer for a
  school fundraiser
• Selecting every 20th name from an alphabetical
  list of all parents and surveying those parents.

13
Random Sampling

• Sample Problem 3
• Which of the following questions is not
  potentially biased?
• Do you prefer creamy macaroni and cheese or
  bland rice?
• Dont you feel the city is wasting money by
  building that new stadium?
• Do you prefer shopping online or in the stores?
• Dont you agree that the driving age should be
  raised to 18 to decrease the number of accidents?

14
Classwork
Practice Worksheet
15
Homework
Page 361 1-7 Page 362 1-2