BSTAT - Ch. 1 Statistics and Data

True. Explanation: A continuous variable is characterized by infinitely uncountable values and can take any value within an interval.

A continuous variable assumes any value from an interval (or collection of intervals).

all items of interest in a statistical problem. Explanation: A population is defined as all members of a specified group under study.

A population consists of

a. Nominal b. Major Number of students Accounting 5 Economics 7 Finance 5 Marketing 3 Management 6 Undecided 4

A professor records the majors of her 30 students as follows: Accounting Economics Undecided Finance Management Management Finance Marketing Economics Management Marketing Finance Marketing Accounting Finance Finance Undecided Management Undecided Economics Economics Accounting Management Undecided Economics Accounting Economics Management Accounting Economics a. What is the measurement scale of these data? b. Summarize the results in tabular form.

False. Explanation: Professor's rank is ordinal but the salary is ratio. A quantitative data with ratio scale of measurement has a meaningful zero point, and hence all ratio values are naturally interpretable.

A professor's rank (assistant, associate, and full), as well as salary, represent ordinal data.

nominal scale Explanation: With nominal data all we can do is categorize or group the data.

A recent survey of 200 small firms (annual revenue less than $10 million) asked whether an increase in the minimum wage would cause the firm to decrease capital spending. Possible responses to the survey question were: "Yes," "No," or "Don't Know." This data is best classified as

ordinal data Explanation: The ordinal scale data can be categorized and ranked.

A respondent of a survey is asked whether the Philadelphia Flyers' performance in the last game was excellent, good, fair, or poor. The person indicates that the performance was "good." This is an example of

a. True. b. Population parameter Explanation b. The value 3.29 represents the population parameter since we are not choosing a sample but drawing results from the actual population.

An accounting professor wants to know the average GPA of the students enrolled in her class. She looks up information on Blackboard about the students enrolled in her class and computes the average GPA as 3.29. a. State whether the following statement is true or false. The population is all students enrolled in the accounting class. b. Does the value 3.29 represent the population parameter or the sample statistic?

cross-sectional data. Explanation: Cross-sectional data refers to data collected by recording a characteristic of many subjects without regard to differences in time.

An analyst studies a data set of the year-end book value per share for all companies listed on the New York Stock Exchange. This data set is best described as

ordinal scale Explanation: A standard way to record the ratings is to use ordinal scale.

At the end of a semester college students evaluate their instructors by assigning them to one of the following categories: Excellent, Good, Average, Below Average, and Poor. The measurement scale is a(n)

The average height of NBA players Explanation: For all other populations, it is very impractical to collect all data. The heights are readily available for all NBA players.

For which of the following population parameters is sampling not necessary?

a. Nominal b. Interval c. Ordinal

In each of the following scenarios, define the type of measurement scale. a. A kindergarten teacher marks whether each student is a boy or a girl. b. A ski resort records the daily temperature during the month of January. c. A restaurant surveys its customers about the quality of its waiting staff on a scale of 1 to 4, where 1 is poor and 4 is excellent.

estimate unknown population parameters and conduct tests about unknown population parameters. Explanation: Inferential statistics is concerned with estimating unknown population parameters and testing hypotheses about them.

In inferential statistics, we calculate statistics of sample data to

a. True. b. Sample statistic.

It came as a big surprise when Apple's touch screen iPhone 4, considered by many to be the best smartphone ever, was found to have a problem (The New York Times, June 24, 2010). Users complained of weak reception, and sometimes even dropped calls, when they cradled the phone in their hands in a particular way. A quick survey at a local store found that 2% of iPhone 4 users experienced this reception problem. a. State whether the following statement is true or false. The population is all iPhone 4 users. b. Does 2% denote the population parameter or the sample statistic?

True. Explanation: With ordinal data we are able both to categorize and rank the data with respect to some characteristic.

Ordinal scale reflects a stronger level of measurement than the nominal scale.

a. The sample consists of 949 elderly people. The population is all elderly people. b. Sample statistics Explanation a. The population is all elderly people. The sample consists of 949 elderly people. b. 22% and 17% represent the sample statistics.

Research suggests that depression significantly increases the risk of developing dementia later in life (BBC News, July 6, 2010). In a study involving 949 elderly persons, it was reported that 22% of those who had depression went on to develop dementia, compared to only 17% of those who did not have depression. a. Choose the relevant population and the sample. b. Do the numbers 22% and 17% represent population parameters or sample statistics?

interval scale. Explanation: Zero in Fahrenheit degrees does not mean "no temperature." We cannot say, for example, that today is twice as warm as six months ago, which characterizes the ratio scale.

The Fahrenheit scale for measuring temperature would be classified as a(n)

True. Explanation: Descriptive statistics refers to the summary of important aspects of a data set.

The branch of statistical studies called descriptive statistics summarizes important aspects of a data set.

U.S. unemployment rate Explanation: It is impossible to gather complete data on the unemployed population of the U.S. Not everyone that is unemployed files for unemployment benefits.

The estimation of which of the following requires sampling?

True. Explanation: Weather forecast is based on a lot of data collected over years.

The weather forecast cannot be based on only the weather for the last three days.

There is a true zero point. Explanation: Only ratio scale data have a true zero point.

Which of the following characteristics does the interval scale not have?

Results of market research testing consumer preferences for soda Explanation: Cross-sectional data refers to data collected by recording a characteristic of many subjects at the same point in time, or without regard to differences in time.

Which of the following is an example of cross-sectional data?

Your last name Explanation: We cannot calculate summary measures if the variable is qualitative in nature.

Which of the following is an example of qualitative data?

Google's closing stock price today Explanation: Google's closing stock price is quantitative data.

Which of the following is an example of quantitative data?

a. Quantitative; discrete b. Qualitative c. Quantitative; continuous

Which of the following variables are qualitative and which are quantitative? If the variable is quantitative, then specify whether the variable is discrete or continuous. a. Points scored in a football game. b. Racial composition of a high school classroom. c. Heights of 15-year-olds.

Temperature Explanation: A quantitative variable assumes meaningful numerical values.

Which of the following variables is quantitative?

descriptive statistics Explanation: Descriptive statistics refers to summarizing a set of data.

Your business statistics class had a test last week. The average score for the class is an example of