1 / 12

Survey

Warm-Up 5/08-09. Determine whether each situation calls for a survey, an experiment, or an observational study. Explain your reasoning. A gaming company plans to test whether a new controller is preferable to the old one.

roland
Download Presentation

Survey

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Warm-Up 5/08-09 Determine whether each situation calls for a survey, an experiment, or an observational study. Explain your reasoning. • A gaming company plans to test whether a new controller is preferable to the old one. • A restaurant wants to know if their customers are satisfied with tt\heir dining experience. Observe a group of teens while using the new and old controllers. Observational study Members of a sample population will be asked questions. Survey

  2. Rigor:You will learn how to use shapes of distributions to select appropriate statistics and to compare data. Relevance:You will be able to analyze real world data by using shapes of distributions to select appropriate statistics and to compare data.

  3. 011-2 Distributions of Data

  4. A distribution of data shows the observed or theoretical frequency of each possible data value. Key Concept: Symmetric and skewed Distributions • Mean  median. • Data are majority on the right of the mean. • Mean  Median. • Data are evenly distributed. • Mean  median. • Data are majority on the left of the mean.

  5. Choosing Appropriate Statistics Symmetric Distribution: use the mean and standard deviation. Skewed Distribution: use the five-number summary

  6. Example 1: Describe a distribution using a histogram. Use a calculator to create a histogram and then describe the distribution. Describe the center and spread of the data. Prices for a random sample of personal computers Positively Skewed Distribution Press [2ND] (Y=) [STAT PLOT] [ENTER] [ENTER] and highlight Adjust window [0, 1000] scl: 100 by [0,10] scl:1 Press [STAT] [ENTER] and enter data values. [STAT] [►][ENTER] [ENTER] Skewed so use five-number summary to describe. Prices range from $374 to $915. Median price is $530.50. Half of the computers are priced between $451.50 and $665.

  7. Key Concept: Box-and Whisker lots as Distributions • Data to the left of median are distributed over wider range than data to the right. • Data have a tail to the left. • Data are evenly distributed. • Data to the right of median are distributed over wider range than data to the left. • Data have a tail to the right.

  8. Example 2: Describe a distribution using a Box-and-Whisker Plot. Use a calculator to create a box-and-whisker plotand then describe the distribution. Describe the center and spread of the data. Average number of minutes all students spent on homework each night. Symmetric Distribution Press [2ND] (Y=) [STAT PLOT] [ENTER] [ENTER] and highlight Adjust window [30, 75] scl: 5 by [0,5] scl:1 Press [STAT] [ENTER] and enter data values. [STAT] [►][ENTER] [ENTER] Symmetric so use mean and SD to describe. The average number of minutes was 53.5 with standard deviation of about 10.5. [▲] [CLEAR] [ENTER]

  9. Example 3: Compare data using histograms. Use a calculator to create a histogram and then describe the distribution. Describe the center and spread of the data. Both distributions are symmetric. Symmetric so use mean and SD to describe. Chapter 3 mean is 81 with SD of about 9.9. Chapter 4 mean is 79 with SD of about 5.9. The mean of chapter 4 is a better representation of the data than the mean of Chapter 3.

  10. Example 4: Compare data using Box-and-Whisker Plot. Use a calculator to create abox-and-whisker plot and then describe the distribution. Describe the center and spread of the data. Points scored per game by a professional football team. Use L1, Plot1 for 2008 and L2, plot2 for 2009. Adjust window [0, 55] scl: 5 by [0,5] scl:1 2008 distribution is negatively skewed. 2009 distribution is positively skewed. Skewed so use five-number summary to describe. [STAT] [►][ENTER] [2nd] [2] [ENTER] 2009 minX= 3 Q1= 6.5 med = 11.5 Q3 = 20.5 maxX = 41 2008 minX= 7 Q1= 20.5 med = 27 Q3 = 30 maxX = 51 75% of 2008 scores > 20.5 while 75% of 2009 scores < 20.5. 25% of 2009 scores < any 2008 score so the team scored higher amount of points in 2008.

  11. Assignment Prob/Stats #6 WS, 1-9 all

More Related