1. What is you’re GPA? Cristian Espinoza Juan Gonzalez Period. 5 2011-2012

2. California Standards 8.0 Students organize and describe distributions of data by using a number of different methods, including frequency tables, histograms, standard line and bar graphs, stem-and-leaf displays, scatter plots, and box- and-whisker plots. 17.0 Students organize 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 simple random sample from a normal distribution.

3. Hypothesis We believe that the average commute GPA for all the students at Century High School is 2.7 GPA.

4. Data Collection Our Sampling technique that was use to collect data was Stratified sampling. We selected 10 random students form each grade level and ask “What is your GPA?” Possible Bias for this sampling technique some might be more into school than others or some might have more harder classes than others as well.

5. Data Length of commute (in GPA) 2.5, 2.5, 2.1, 2.7, 3.1, 3.3, 2.7, 2.5, 2.7, 2.2, 2.5, 2.5, 4.0, 2.3, 2.8, 4.0, 4.0, 3.8, 3.1, 2.8, 3.2, 3.2, 2.7, 3.6, 2.5, 4.3, 3.3, 3.8, 2.6, 2.4, 3.3, 3.2, 2.0, 1.8, 2.8, 2.9, 2.6, 3.8, 3.7, 3.2

6. Histogram

7. Statistics For our survey, Student’s sample commute sample mean GPA is 2.975 with sample standard deviation of.6188.

8. Confidence Interval 95% Confidence Interval Z-interval (2.783,3.166) We are 95% confident mean commute GPA for students is anywhere between 2.783 to 3.166 GPA.

9. Hypothesis Testing Test Hypothesis Hypothesis testing: test at Claim: we believe that the average “GPA” is 2.7 Test statistics (z test) P- value =.0049< = 0.05 At 5% level of significance we reject the There is not enough evidence to support our claim.

10. Error Analysis Our sample mean is 2.975 GPA, with a 95% level of confidence for the population mean is between 2.783 to 3.166 GPA. With a margin of error is about.883 GPA. Our sample error might be the lack of people ask during the survey and we may need more student’s GPA in our survey to get a more accurate population mean result.

11. Conclusion We hypothesized that the average GPA for all the students at Century High School is 2.7. In our survey of 40 students, we find the sample mean of 2.975 GPA with a standard deviation of.6188 GPA. We concluded the population for all students at Century high school is between 2.783 to 3.166 with a 95% confidence interval.