STAT Chapter 1 Homework
Explain the difference between a discrete and a continuous variable
Discrete variables can assume only certain values , but continuous variables can assume any values
For the following situations, would you collect information using a sample or a population? Statistics 201 is a course taught at a university. Professor Rauch has taught nearly 1,500 students in the course over the past 5 years. You would like to know the average grade for the course based on all 1,500 students. Population Sample As part of a research project, you need to report the average profit as a percentage of revenue for the #1-ranked corporation in the Fortune 500 for each of the last 10 years. Population Sample You are looking forward to graduation and your first job as a salesperson for one of five large pharmaceutical corporations. Planning for your interviews, you will need to know about each company's mission, profitability, products, and markets. Population Sample You are shopping for a new MP3 music player such as the Apple iPod. The manufacturers advertise the number of music tracks that can be stored in the memory. Usually, the advertisers assume relatively short, popular songs to estimate the number of tracks that can be stored. You, however, like Broadway musical tunes and they are much longer. You would like to estimate how many Broadway tunes will fit on your MP3 player. Population Sample
a. Population b. Population c. Population d. sample Explanation a. A population is used because the professor likely has grades readily available from every student over the past 5 years. b. A population is employed because the information is easy to find and there are only 10 observations in the entire population. c. A population is used because the information is easy and relatively quick to collect for only five companies. d. A sample works because it is difficult to locate every musical and the length of every song.
Explain the difference between qualitative and quantitative variables.
qualitative data is not numerical quantitative data is numerical
A poll solicits a large number of college undergraduates for information on the following variables: the name of their cell phone provider (AT&T, Verizon, and so on), the numbers of minutes used last month (200, 400, for example), and their satisfaction with the service (Terrible, Adequate, Excellent, and so forth). What is the level of measurement for each of these three variables? The cell phone provider The number of minutes used Satisfaction with the service
The cell phone provider- Nominal The number of minutes used - Ratio Satisfaction with the service - Ordinal Explanation The cell phone providers are different from each other but have no meaning other than identification. So they are nominal level of measurement. The minutes used has a significant zero point and the ratio between two numbers meaningful. So they are ratio level of measurement. Satisfaction ratings are higher or lower than one another, but the differences between them are not the same. So the satisfaction ratings are ordinal level of measurement.
Slate is a daily magazine on the Web. Its business activities can be described by a number of variables. What is the level of measurement for each of the following variables? a. The number of hits on their website on Saturday between 8:00 a.m. and 9:00 a.m. b. The departments, such as food and drink, politics, foreign policy, sports, etc. c. The number of weekly hits on the Sam's Club ad. d. The number of years each employee has been employed with Slate.
a. Ratio b. Nominal c. Ratio d. Ratio Explanation a. The number of hits on their web site on Saturday has a significant zero point and the ratio between two numbers meaningful. So they are ratio level of measurement. b. The departments are different from each other but have no meaning other than identification. So they are nominal level of measurement. c. The number of weekly hits on the Sam's Club ad has a significant zero point and the ratio between two numbers meaningful. So they are ratio level of measurement. d. The number of years each employee has been employed has a significant zero point and the ratio between two numbers meaningful. So they are ratio level of measurement.
Classify the following as a population or sample: a. 1000 TV viewers chosen from the state of Texas to find the popularity of TV serials. Sample Population b. All the books in a newly opened bookshop. Sample Population
a. Sample b. Population Explanation A population is the entire group which you are studying. A sample is a subset taken from a population.
The Wall Street Journal's website, www.wsj.com, reported the total number of cars and light-duty trucks sold through February of 2016 and February of 2017. The top 16 of 29 manufacturers are listed here. Sales data often are reported in this way to compare current sales to last year's sales. See the data file for the complete list and use it to respond to the following questions. Year-to-Date Sales ManufacturerThrough February 2017 Through February 2016 General Motors Corp. 433,049 431,570 Ford Motor Company 378,650 388,523 Toyota Motor Sales USA Inc. 317,387 349,238 Chrysler 315,684 353,525 Nissan North America Inc. 248,059 236,645 American Honda Motor Co Inc. 228,066 219,482 Hyundai Motor America 99,527 98,020 Subaru of America Inc. 89,379 83,112 Kia Motors America Inc. 78,299 88,042 Mercedes-Benz 54,611 51,773 Volkswagen of America Inc. 48,655 42,400 Mazda Motor of America Inc. 44,522 41,247 BMW of North America Inc. 40,667 40,580 Audi of America Inc. 26,942 23,568 Mitsubishi Motors N A Inc. 17,381 14,134 Volvo 8,123 9,504 Required a. Using computer software, compare the 2016 year-to-date sales through February to the 2017 year-to-date sales through February for each manufacturer by computing the difference. Using computer software, sort the list of the manufacturers in order of largest to smallest difference in year-to-date sales. Which manufacturers are in the top five with increased sales? Which manufacturers are in the bottom five with decreased sales? b. For each manufacturer, compare 2016 year-to-date sales through February to 2017 year-to-date sales through February by computing the percentage change in year-to-date sales using computer software. Using computer software, sort the list of manufacturers from largest to smallest using the percentage change. Which manufacturers are in the top five in percentage change? Which manufacturers are in the bottom five in percentage change? (Enter your answers as a whole percentage.) c--1. Using computer software, sort the list of manufacturers from largest to smallest using 2017 year-to-date sales through February. Then, design a bar graph to illustrate the 2016 and 2017 year-to-date sales through February for the top 12 manufacturers.
a. Top Five Manufacturer Nissan North America Inc. 11,414 American Honda Motor Co Inc.s 8,584 Subaru of America Inc. 6,267 Volkswagen of America Inc. 6,255 Audi of America Inc. 3,374 Volvo -1,381 Kia Motors America Inc. - -9,743 Ford Motor Company - -9,873 Toyota Motor Sales USA Inc. - -31,851 Chrysler - -37,841 b. Mitsubishi Motors N A Inc. 23t% Volkswagen of America Inc. 15% Audi of America Inc. 14s% Mazda Motor of America Inc. 8% Subaru of America Inc.8% Ford Motor Compan -3% Toyota Motor Sales USA Inc. -9% Chrysler -11% Kia Motors America Inc. -11% Volvo -15%
