Transcript How Many Fights Have You Been In Since You Been Here At Century

HOW Many fights have you
been in since you been here at
century
JESSICA NESTOR & JACKQUELINE RENTERIA
PERIOD:06
2011-2012
California Standards
 8.0: Students organize and describe distribution of
data by using a number of different methods,
including frequency tables, histograms, standard
line and bar graphs, stem-and-leaf displays,
scatterplots, and box-and-whisper plots.
 17.0: Students determine confidence intervals for a
simple random sample from a normal distribution
of data and determine the sample size required for
a desired margin of error.
 18.0: Students determine the P-value for a statistic
for a sample random sample for a normal
distribution.
Hypothesis
• We believe that during four years here
at Century High School, an average
amount of fights for a student would be
around two fights.
Data Collection
Random, we asked random
people that we saw walking
around the campus.
We asked a total of forty
people.
We collected our data by
walking around the campus and
we asked forty Century
students.
Data
Number of times students got into
fights.
7,2,3,6,6,0,1,1,1,0,3,2,5,2,0,6,7,3,9,4,3,3,
4,2,2,1,6,5,1,2,0,2,2,1,6,4,2,0,0,3
Histogram
How Many Fights Have You Been In Since You Been Here At Century
Number Of People
14
12
10
8
6
4
2
0
0.75
2.25
3.75
5.25
6.75
Number Of Fights
8.25
9.75
Statistics
From our survey the average
amount of fights is 3.97 fights
with sample standard
deviation 4.51.
Hypothesis Testing
• I believe the average amount of fights is two.
• H 0 :   2(claim )
Ha :   2
• At 5% level significance, we failed to reject the
• There is enough evidence to support our
claim.
Confidence Interval




95% Confidence Interval
Z-Interval
(2.2124,3.6376)
We are 95% confident that the average
amount of fights a student who attends four
years here at Century will get into is between
2.2124 to 3.6376.
Conclusion
• We hypothesis that the average fights
that Century High School students who
attend four years here at Century are
involved in is 3 times. In our survey of 40
centurions, we found the sample mean of
3.97 Times with a standard deviation of
4.51 times. We conclude that the
population mean for all centurions is
between 2.21 times to 3.63 times with 95%
confidence. We test our initial
hypothesis with 5% level of significance,
and confirm our hypothesis is correct.
ERROR ANALYSIS
• Our sample mean is 3.97 fights and the
95% Confidence level for the
population mean is between 2.2124 To
3.6376 THE marginal error is about
.34 fights.
• OUR SAMPLE ERROR IS DUE TO POSSIBLE
UNDERREPRESENTATION OF THE
POPULATION . We might need to take
more samples due to the teacher
absences people fail to check their
survey in the e-mail