1. Alan Flores, Kathy Alvarado, Carol Prieto Period: 5 2011-2012

2. 8.0 Students organize and describe distributions of data by using a number of different methods, including frequency table, histograms, standards line and bar graphs, stem-and –leaf displays, scatter plots, and box-and-whisker 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-valve for a statistic for a simple random sample from a normal distribution.

3. We believe that the amount to take a shower is 30 minutes.

4. We will collect data by using the random sampling method. We ask every third person we see walking around school.

5. Length of shower 25,15,25,30,30,10,15,15,20,25,10,20,10,15,11,15,8,20,10,6,17,25,21,20,13,9,10,10,15,8,12,25,10,5,20,6,10,10,11,19,12,13

7. Find sample mean and sample standard deviation. Stat → test → 1 var stat Sample mean x = 15.1428 Sample Standard deviation sx=6.6426

8. Find 95% confidence interval STAT→ Test→ 7. z-interval→ Select “stats” Calculate: (13.13, 17.15) Conclusion: We are 95% confident that the population mean of how long do you take to shower is between 13.13 and 17.15 minutes.

9. Claim: We believe that the amount to take a shower is 30 minutes. Test Statistics (z-test) At 5% level of significance we reject the claim that there is not enough evidence to support our claim (hypothesis)

10. Our sample mean is 15.1428 minutes, and the 95% confidence level for the population mean is between 13.134 to 17.152 minutes. The marginal error is about 2.0092 minutes. Our sample error is due to possible under- representation of the population. We might need to take more samples due to people taking a shower, people fail to check their survey by asking students.

11. We are 95% confident that the population mean how long do you take to shower is between (13.134 min to 17.152 min )