Transcript Math 2 Model Classroom - Loganville High School

How is data presented,
compared and used to predict
future outcomes?
The standards for this domain…
MM1D1
Students will determine the number of outcomes related to a given event.
MM1D2
Students will use the basic laws of probability.
MM1D3
Students will relate samples to a population.
MM2D1
Using sample data, students will make informal inferences about population
means and standard deviations.
MM2D2
Students will determine an algebraic model to quantify the association between
two quantitative variables.
SAMPLES– MM1D3
• Summary Statistics
• Population vs Sample
• Representative Sample -Random
Summary Statistics
Mean
5 number summary
(Box & Whisker Plot)
Range
Mean
Average
5 NUMBER SUMMARY – BOX & WHISKER PLOT
Range
How far from the lowest
value to the highest
value
(subtract)
Now you try one…
Linda's first five Math II tests scores
were 75, 82, 74, 95, and 89. If
her mean semester average was
85, what score did she make on
her sixth and last test?
95
Which would be better
median or mean?
If each of the 20 random samples
collected contains several outliers,
which of the following will give the
best estimate of where the center of
the actual population lies?
Median because it is more
resistant to outliers.
Population vs Sample
Sample is the PART of the
population that you
survey for your study.
The key is selecting a
representative sample.
Representative Sample
• The sample must be Random!
• The larger the sample the closer to
the population.
• If a small sample, the more samples
the closer to the population.
Example
A population was sampled ten times.
The medians of the samples are:
17, 17, 17, 18, 19, 19, 20, 20, 21, 21
Can we use these sample medians to
predict the median of the population?
Example answer
YES – take the mean of the sample
medians which would be 18.9
So a good estimate of the median of the
actual population would be 19.
Representative Sample
Random is always
representative.
Sample Types
Self selected – volunteer
Systematic – rule or pattern
Convenience – easy to contact
Biased – skewed – not representative
Unbiased – representative of the
population
Example…
Janet is surveying students at her school. Which of the following
would most likely give her a representative sample?
a. Surveying only her homeroom
b. Surveying the first 60 students who walk up to her at lunch
c. Surveying only the members of the school chorus
d. Surveying 50 students from each grade who have been
randomly selected by a computer.
D – why?
WHY? what type of sample…
What type of samples are these and what is wrong with them?
a. Surveying only her homeroom -- convenience
b. Surveying the first 60 students who walk up to her at
lunch-- volunteer
c. Surveying only the members of the school chorus -biased
d. Surveying 50 students from each grade who have been
randomly selected by a computer. -- systematic
Now you try one…
A principal is surveying the parents of his students to find out if
they would support extending the school day by 20 minutes.
Which method would most likely result in a representative
sample?
a. Surveying every 20th name from a list of all school parents
b. Surveying 50 parents of ninth graders.
c. Surveying parents that attend the monthly PTO meeting
d. Surveying parents who volunteer in the media center.
A
More Practice
Handout