HW1

Martial status is what type of variable? A. Categorical B. Numerical, continuous C. Numerical, discrete

A. Categorical

Previous loan payments of $304 is what type of variable? A. Numerical, continuous B. Numerical, discrete C. Categorical

A. Numerical, continuous

The number of children is what type of variable? A. Numerical, discrete B. Numerical, continuous C. Categorical

A. Numerical, discrete

The chancellor of a major university was concerned about alcohol abuse on her campus and wanted to find out the proportion of students at her university who visited campus bars on the weekend before the final exam week. Her assistant took a random sample of 250 students and computed the portion of students in the sample who visited campus bars on the weekend before the final exam. The portion of all students at her university who visited campus bars on the weekend before the final exam week is an example of which of the following? A. a parameter. B. a statistic. C. a categorical variable. D. a discrete variable.

A. a parameter.

Which of the following yields a systematic sample? A. All students in a class are grouped according to their gender. A random sample of 8 is selected from the males and a separate random sample of 7 is drawn from the females. B. All students in a class are divided into groups of 15. One student is randomly chosen from the 1st group, the remaining observations are every 15th student thereafter. C. A random sample of 15 students is selected from a class without replacement. D. The best 15 students, according to the opinion of the instructor, in a class are selected.

B. All students in a class are divided into groups of 15. One student is randomly chosen from the 1st group, the remaining observations are every 15th student thereafter.

An academic major is what type of variable? A. Numerical, continuous B. Categorical C. Numerical, discrete

B. Categorical

Nationality is what type of variable? A. Numerical, discrete B. Categorical C. Numerical, continuous

B. Categorical

Whether telephone service in a household is provided by the household's Internet provider is what kind of variable? A. Discrete numerical B. Categorical C. Continuous numerical

B. Categorical

The length (in minutes) of a person's commute to work is what kind of variable? A. Discrete numerical. B. Continuous numerical. C. Categorical

B. Continuous numerical.

The number of landline telephones in the household is what kind of variable? A. Categorical B. Discrete numerical C. Continuous numerical

B. Discrete numerical

The number of students in a class is what kind of variable? A. Categorical B. Discrete numerical C. Continuous numerical

B. Discrete numerical

Suppose that you measure the time it takes to download a video from the internet. Explain why the download time is a continuous numerical variable. A. Download time is a continuous numerical variable because it has numerical values that arise from a counting process. B. Download time is a continuous numerical variable because it has numerical values that arise from a measuring process. C. Download time is a continuous numerical variable because it has values that can only be placed into categories.

B. Download time is a continuous numerical variable because it has numerical values that arise from a measuring process.

Expected time until return is what type of variable? A. Numerical, discrete B. Numerical, continuous C. Categorical

B. Numerical, continuous

The number of computers owned is what type of variable? A. Categorical B. Numerical, discrete C. Numerical, continuous

B. Numerical, discrete

Which of the following types of sample can you use if you want to make valid statistical inferences from a sample to a population? A. a quota sample. B. a probability sample. C. a convenience sample. D. a judgement sample.

B. a probability sample.

A summary measure that is computed to describe a characteristic from only a sample of the population is called... A. a summary table. B. a statistic. C. a parameter. D. an ordered array.

B. a statistic.

The chancellor of a major university was concerned about alcohol abuse on her campus and wanted to find out the proportion of students at her university who visited campus bars on the weekend before the final exam week. Her assistant took a random sample of 250 students. The portion of students in the sample who visited campus bars on the weekend before the final exam week is an example of... A. a categorical variable. B. a statistic. C. a summary table. D. a parameter.

B. a statistic.

A newspaper poll asked 2,150 adults in a country a series of questions to find out their view on their country's economy. The population of interest is which of the following? A. All the people living in the country when the poll was taken. B. All the females living in the country when the poll was taken. C. All the adults living in the country when the poll was taken. D. All the males living in the country when the poll was taken.

C. All the adults living in the country when the poll was taken.

Travel outside the country is what type of variable? A. Numerical, discrete B. Numerical, continuous C. Categorical

C. Categorical

Whether an individual has a television is what kind of variable? A. Discrete numerical B. Continuous numerical C. Categorical

C. Categorical

The time in hours spent working per week is what kind of variable? A. Categorical B. Discrete numerical C. Continuous numerical

C. Continuous numerical

Which of the 4 methods of data collection is involved when a person counts the number of cars passing designed locations on a city's expressway system? A. Experimentation B. Surveying C. Observation D. Published sources

C. Observation

Suppose that 10,000 customers in a retailer's customer database are categorized by three customer types: 3,500 prospective buyers, 4,500 first time buyers, and 2,000 repeat (loyal) buyers. A sample of 1,000 customers is needed. 1. What type of sampling should you do? Why? A. Convenience sample for efficiency. B. Systematic sample for accuracy. C. Stratified sample for efficiency. D. Simple random sample for accuracy. 2. Explain how you would carry out the sampling according to the method stated in question number one. A. Select a simple random sample from each of the three types of customers and combine the results. B. Take the highest number of samples from the stratum that seems the most representative, and take the lowest number of samples from the stratum that is most likely to produce outliers. C. Partition the N customers in the frame into n groups of k customers, where k=N/n, rounding to the nearest integer. Next, choose the first customer to be selected at random from the first k customers in the frame. Then, select the remaining n-1 customers by taking every kth customer thereafter from the entire frame. D. Take a simple random sample of 500 of the customers out of all of the customers, disregarding which stratum each customer belongs to. 3. Why is the sampling in number one not simple random sampling? A. A simple random sample gives every item from a frame the same chance of selection as every other item, which is not true with this sampling method. B. In a simple random sample, each customer must be replaced in the sample after being chosen, which is not true with this sampling method. C. The probability of selection for each customer must be known, which is not true with this sampling method. D. A simple random sample gives every sample of a fixed size the same chance of selection as every other sample of that size, which is not true with this sampling method.

C. Stratified sample for efficiency. A. Select a simple random sample from each of the three types of customers and combine the results. D. A simple random sample gives every sample of a fixed size the same chance of selection as every other sample of that size, which is not true with this sampling method.

Which of the following yields a simple random sample? A. The best 15 students, according to the opinion of the instructor, in a class are selected. B. All students in a class are divided into groups according to the rows that they are seated. One of the groups is randomly selected. C. The names of 50 students in a class are written on 50 different pieces of paper and put in a hat. The first 15 pieces of paper are selected blindly one at a time after shuffling the papers thoroughly and each of the selected pieces is placed back into the hat before the next piece is selected. D. All students in a class are grouped according to their gender. A random sample of 8 is selected from the males and a separate random sample of 7 is drawn from the females.

C. The names of 50 students in a class are written on 50 different pieces of paper and put in a hat. The first 15 pieces of paper are selected blindly one at a time after shuffling the papers thoroughly and each of the selected pieces is placed back into the hat before the next piece is selected.

A newspaper poll asked 2,150 adults in a country a series of questions to find out their view on their country's economy. The 2,150 adults make up which of the following? A. the population. B. the primary data source. C. the sample. D. the secondary data source.

C. the sample.

Which of the following yields a cluster sample? A. The best 15 students, according to the opinion of the instructor, in a class are selected. B. All students in a class are grouped according to their gender. A random sample of 8 is selected from the males and a separate random sample of 7 is drawn from the females. C. All students in a class are divided into groups of 15. One student is randomly chosen from the 1st group, the remaining observations are every 15th student thereafter. D. All students in a class are divided into groups according to the rows that they are seated. One of the groups is randomly selected.

D. All students in a class are divided into groups according to the rows that they are seated. One of the groups is randomly selected.

Which of the following yields a stratified sample? A. The best 15 students, according to the opinion of the instructor, in a class are selected. B. A random sample of 15 students is selected from a class without replacement. C. All students in a class are divided into groups of 15. One student is randomly chosen from the 1st group, the remaining observations are every 15th student thereafter. D. All students in a class are grouped according to their gender. A random sample of 8 is selected from the males and a separate random sample of 7 is drawn from the females.

D. All students in a class are grouped according to their gender. A random sample of 8 is selected from the males and a separate random sample of 7 is drawn from the females.

The evening host of a dinner dance reached into a bowl, mixed all the tickets around, and selected the ticket to award the grand door prize. What sampling method was used? A. Stratified sample. B. Cluster sample. C. Systematic sample. D. Simple random sample.

D. Simple random sample.

Businesses in a country are listed by size: small, medium, and large. Explain why business size is an example of a categorical variable. A. The size of a business is categorical because it has values that represent qualities. B. The size of a business is categorical because it has numerical values that arise from a measuring process. C. The size of a business is categorical because it has numerical values that arise from a counting process. D. The size of a business is categorical because it has values that can only be placed into categories.

D. The size of a business is categorical because it has values that can only be placed into categories.

Four different beverages are sold at a fast-food restaurant: soft drinks, tea, coffee, and bottled water. Explain why the type of beverage sold is an example of a categorical variable. A. Types of beverage sold is a categorical variable because the values of the variable arise from a counting process. B. Types of beverage sold is a categorical variable because the values of the variable arise from a measuring process. C. Types of beverage sold is a categorical variable because the values of the variable represent quantities. D. Types of beverage sold is a categorical variable because the values of the variable can only be placed into categories.

D. Types of beverage sold is a categorical variable because the values of the variable can only be placed into categories.

To demonstrate a sampling method, the instructor in a class picked the first 5 students sitting in the last row of the class. This is an example of which of the following? A. systematic sample. B. stratified sample. C. simple random sample. D. convenience sample.

D. convenience sample.