Business Statistics Chapter 1
a. What is the average cost for the tablets (to 2 decimals)? 559.14 b. Compare the average cost of tablets with a Windows operating system to the average cost of tablets with an Android operating system (to 2 decimals). 689.00 = average cost for Windows operating system 329.50 = average cost for Android operating system c. What percentage of tablets use a CPU manufactured by TI OMAP (to the nearest percent)? 14% d. What percentage of tablets use an Android operating system (to the nearest percent)? 29%
Refer to Table in image. a. What is the average cost for the tablets (to 2 decimals)? b. Compare the average cost of tablets with a Windows operating system to the average cost of tablets with an Android operating system (to 2 decimals). c. What percentage of tablets use a CPU manufactured by TI OMAP (to the nearest percent)? d. What percentage of tablets use an Android operating system (to the nearest percent)?
A. What is the population of interest in this study? BusinessWeek North America subscribers B. Is annual income a categorical or quantitative variable? Quantitative C. Is ownership of an American Express card a categorical or quantitative variable? Categorical D. Does this study involve cross-sectional or time series data? Cross-sectional E.Determine whether the following two statistical inferences may be made based on the sample data collected. An estimated 59% of the population of subscribers has an annual income of $75,000 or more? DATA SUPPORTS INFERENCE An estimated 60% of the population of subscribers has an American Express credit card? DATA DOES NOT SUPPORT INFERENCE
A Bloomberg BusinessWeek North American subscriber study collected data from a sample of 2,861 subscribers. Fifty-nine percent of the respondents indicated an annual income of $75,000 or more, and 50% reported having an American Express credit card. A. What is the population of interest in this study? B. Is annual income a categorical or quantitative variable? C. Is ownership of an American Express card a categorical or quantitative variable? D. Does this study involve cross-sectional or time series data? E.Determine whether the following two statistical inferences may be made based on the sample data collected. An estimated 59% of the population of subscribers has an annual income of $75,000 or more? An estimated 60% of the population of subscribers has an American Express credit card?
The personnel department? INTERNAL The department of labor? EXTERNAL Other industry associations?EXTERNAL
A manager of a large corporation recommends a $10,000 raise be given to keep a valued subordinate from moving to another company. Consider the internal and external sources of data that might be used to decide whether such a salary increase is appropriate. Classify each of the following sources of data on employee salaries as either internal or external. The personnel department? The department of labor? Other industry associations?
This study compared two populations. What were the populations? WOMEN WHOS MOMS TOOK DES DURING PREGNANCY AND THOSE WHOS MOMS DID NOT Do you suppose the data were obtained in a survey or in an experiment?SURVEY For the population of women whose mothers took the drug DES during pregnancy, a sample of 3980 women showed that 63 developed tissue abnormalities that might lead to cancer. Provide a descriptive statistic (to 1 decimal) that could be used to estimate the number of women out of 1,000 in this population who have tissue abnormalities? 15.8/1,000 For the population of women whose mothers did not take the drug DES during pregnancy, what is the estimate (to 1 decimal) of the number of women out of 1,000 who would be expected to have tissue abnormalities? (Hint: remember that women whose mothers took the drug were twice as likely to develop tissue abnormalities.) 7.9/1,000 True or false: medical studies often use a relatively large sample (in this case, 3980) because disease occurrences can be rare and difficult to observe when only isolated populations are considered.TRUE
A seven-year medical research study reported that women whose mothers took the drug DES during pregnancy were twice as likely to develop tissue abnormalities that might lead to cancer as were women whose mothers did not take the drug. This study compared two populations. What were the populations? Do you suppose the data were obtained in a survey or in an experiment? For the population of women whose mothers took the drug DES during pregnancy, a sample of 3980 women showed that 63 developed tissue abnormalities that might lead to cancer. Provide a descriptive statistic (to 1 decimal) that could be used to estimate the number of women out of 1,000 in this population who have tissue abnormalities? For the population of women whose mothers did not take the drug DES during pregnancy, what is the estimate (to 1 decimal) of the number of women out of 1,000 who would be expected to have tissue abnormalities? (Hint: remember that women whose mothers took the drug were twice as likely to develop tissue abnormalities.) True or false: medical studies often use a relatively large sample (in this case, 3980) because disease occurrences can be rare and difficult to observe when only isolated populations are considered.
a. What is the variable of interest? Google revenue in billions of dollars b. Are the data categorical or quantitative? Quantitative c. Are the data time series or cross-sectional? Time series
Figure 1.7 provides a bar chart showing the annual revenue for Google from 2005 to 2014. a. What is the variable of interest? b. Are the data categorical or quantitative? c. Are the data time series or cross-sectional?
a. Do the responses for this question provide categorical or quantitative data? CATEGORICAL b. What was the sample size for this gallup poll? 1018 c. What percentage of respondents would vote for a law increasing the gas tax (to the nearest whole number)? 29% d. Do the results indicate general support for or against increasing the gas tax to improve roads and bridges and build more mass transportation? Support against
In a gallup telephone survey conducted on April 9-10, 2013, the person being interviewed was asked if he would vote for a law in his state that would increase the gas tax up to 20 cents a gallon, with the new gas tax money going to improve roads and bridges and build more mass transportation in his state. Possible responses were vote for, vote against, and no opinion. Two hundred ninety five respondents said they would vote for the law, 672 said they would vote against the law, and 51 said they had no opinion (gallup website, June 14, 2013). a. Do the responses for this question provide categorical or quantitative data? b. What was the sample size for this gallup poll? c. What percentage of respondents would vote for a law increasing the gas tax (to the nearest whole number)? d. Do the results indicate general support for or against increasing the gas tax to improve roads and bridges and build more mass transportation?
a. One statistic concerned using cell phones or tablet computers for local news. What population is that finding applicable to? ALL AMERICAN ADULTS b. Another statistic concerned using cell phones or tablet computers to check local weather reports and to find local restaurants. What population is this finding applicable to? AMERICAN ADULTS THAT OWN A CELLPHONE/TABLET COMPUTER
Pew Research Center is a nonpartisan polling organization that provides information about issues, attitudes, and trends shaping America. In a poll, Pew researchers found that 47% of American adult respondents reported getting at least some local news on their cell phone or tablet computer (Pew Research website, May 14, 2011). Further findings showed that 42% of respondents who own cell phones or tablet computers use those devices to check local weather reports and 37% use the devices to find local restaurants or other businesses. a. One statistic concerned using cell phones or tablet computers for local news. What population is that finding applicable to? b. Another statistic concerned using cell phones or tablet computers to check local weather reports and to find local restaurants. What population is this finding applicable to?
a. What is the average price for the cordless telephones (to 2 decimals)? 68.13 b. What is the average talk time for the cordless telephones (to 3 decimals)? 8.875 c. What percentage of the cordless telephones have a voice quality of excellent? 25% d. What percentage of the cordless telephones have a handset on the base? 50%
Refer to the data set in Table 1.7 as shown below: a. What is the average price for the cordless telephones (to 2 decimals)? b. What is the average talk time for the cordless telephones (to 3 decimals)? c. What percentage of the cordless telephones have a voice quality of excellent? d. What percentage of the cordless telephones have a handset on the base?
Determine whether the following statement concerning statistics is true or false. Statistics can be referred to as numerical facts. In a broader sense, statistics is the field of study dealing with the collection, analysis, presentation and interpretation of data. a. True b. False
TRUE
a. How many elements are in this data set? 9 b. How many variables are in this data set? 5 c. Which variables are categorical and which variables are quantitative? Cost($) = QUANTITATIVE Operating System = CATEGORICAL Display Size (inches) = QUANTITATIVE Battery Life (hrs) = QUANTITATIVE CPU Manufacturer = CATEGORICAL d. What type of measurement scale is used for each of the variables? Cost($) = RATIO Operating System = NOMINAL Display Size (inches) = RATIO Battery Life (hrs) = RATIO CPU Manufacturer = NOMINAL
Tablet PC Comparison provides a wide variety of information about tablet computers. The company's website enables consumers to easily compare different tablets using factors such as cost, type of operating system, display size, battery life, and CPU manufacturer. A sample of 9 tablet computers is shown in the table below. a. How many elements are in this data set? b. How many variables are in this data set? c. Which variables are categorical and which variables are quantitative? Cost($) Operating System Display Size (inches) Battery Life (hrs) CPU Manufacturer d. What type of measurement scale is used for each of the variables? Cost($) Operating System Display Size (inches) Battery Life (hrs) CPU Manufacturer
A. Is type of business a categorical or quantitative variable? CATEGORICAL B. What percentage of the applications came from small businesses (to 1 decimal)? 42.3%
The Commerce Department reported receiving the following applications for the Malcolm Baldrige National Quality Award: 23 from large manufacturing firms, 18 from large service firms, and 30 from small businesses. A. Is type of business a categorical or quantitative variable? B. What percentage of the applications came from small businesses (to 1 decimal)?
a. Is the data collected by Kroger in this example categorical or quantitative? CATEGORICAL b. What measurement scale is used? NOMINAL
The Kroger Company is one of the largest grocery retailers in the United States, with over 2000 grocery stores across the country. Kroger uses an online customer opinion questionnaire to obtain performance data about its products and services and learn about what motivates its customers (Kroger website, April 2012). In the survey, Kroger customers were asked if they would be willing to pay more for products that had each of the following four characteristics. The four questions were: Would you pay more for products that have a brand name? products that are environmentally friendly? products that are organic? products that have been recommended by others? For each question, the customers had the option of responding yes if they would pay more or no if they would not pay more. a. Is the data collected by Kroger in this example categorical or quantitative? b. What measurement scale is used?
A. How many variables are in the data set? 5 B. Of the following subset of variables, indicate which are categorical and which are quantitative. EXCHANGE = Categorical PRICE/EARNINGS RATIO = Quantitative GROSS PROFIT MARGIN (%) = Quantitative C. For the Exchange variable, show the frequency and the percent frequency for AMEX, NYSE, and OTC. FREQUENCY % FREQUENCY AMEX 5 20 NYSE 3 12 OTC 17 68 Total 25 100 D. Show the frequency distribution for the Gross Profit Margin using the five intervals below: GROSS PROFIT MARGIN FREQUENCY 0-14.9, 2 15-29.9, 6 30-44.9, 8 45-59.9, 6 60-74.9 3
The following table shows a data set containing information for 25 of the shadow stocks tracked by the American Association of Individual Investors (aaii.com, February 2002). Shadow stocks are common stocks of smaller companies that are not closely followed by Wall Street analysts A. How many variables are in the data set? B. Of the following subset of variables, indicate which are categorical and which are quantitative. EXCHANGE PRICE/EARNINGS RATIO GROSS PROFIT MARGIN (%) C. For the Exchange variable, show the frequency and the percent frequency for AMEX, NYSE, and OTC. FREQUENCY % FREQUENCY AMEX NYSE OTC Total D. Show the frequency distribution for the Gross Profit Margin using the five intervals below: GROSS PROFIT MARGIN FREQUENCY 0-14.9, 15-29.9, 30-44.9, 45-59.9, 60-74.9