BUS219 -  A few years ago, it came as a surprise when Apple’s iPhone

Business Statistics: Chapter 1

Claudia Pena

BUS219

Book Exercises Chapter 1

Section 1.1

1.) A few years ago, it came as a surprise when Apple’s iPhone 4 was found to have a problem. Users complained of weak reception, and sometimes even dropped calls, when they cradled the phone in their hands in a particular way. A survey at a local store found that 2% of iPhone 4 users experienced this reception problem.

a. Describe the relevant population.

·b. Is 2% associated with the population or the sample?

·2.) (#5) Research suggests that depression significantly increases the risk of developing dementia later in life. Suppose that in a study involving 949 elderly persons, it was found that 22% of those who had depression went on to develop dementia, compared to only 17% of those who did not have depression.

a. Describe the relevant population and the sample.

·b. Are the numbers 22% and 17% associated with the population or a sample?

3.) (#7) Go to www.finance.yahoo.com to get the current stock quote for Home Depot (ticker symbol = HD). Use the ticker symbol to search for historical prices and create a table that includes the monthly adjusted close price of Home Depot stock for the last 12 months. Do these data represent cross-sectional or time series data?

4.) (#8) Go to The New York Times website at www.nytimes.com and review the front page. Would you consider the data on the page to be structured or unstructured? Explain.

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Section 1.2

1.) (#12) Which of the following variables are categorical and which are numerical? Respond to a, b, and c. If the variable is numerical, 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.

2.) (#15) In each of the following scenarios, define the type of measurement scale.

a. An investor collects data on the weekly closing price of gold throughout the year.

b. An analyst assigns a sample of bond issues to one of the following credit ratings, given in descending order of credit quality (increasing probability of default): AAA, AA, BBB, BB, CC, D.

c. The dean of the business school at a local university categorizes students by major (i.e., accounting, finance, marketing, etc.) to help in determining class offerings in the future.

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