1.
A Virginia restaraunt determines its customers' political preferences by whether they buy the red or blue tortilla chips. (True story) This is an example of what kind of sampling?
Correct Answer
B. Convenience
Explanation
This is an example of convenience sampling because the restaurant is only considering the preferences of the customers who choose to buy tortilla chips. It is not randomly selecting customers or considering a representative sample of the population.
2.
Social security number is what kind of value?
Correct Answer
A. Categorical
Explanation
A social security number is a unique identifier assigned to individuals for the purpose of tracking their employment history and benefits. It is not a numerical value that can be measured or compared quantitatively. Instead, it falls into a specific category or group, making it a categorical value.
3.
Odometer reading is what king of value?
Correct Answer
D. Ratio
Explanation
The correct answer is "Ratio" because an odometer reading represents a continuous numerical value that has a meaningful zero point, allowing for meaningful comparisons and calculations. A ratio scale measurement is the highest level of measurement, providing the most precise and comprehensive information. In this case, the odometer reading can be used for various calculations such as distance traveled, fuel efficiency, and maintenance intervals.
4.
To study television commericals, we randomy sample several television channels and sample every commercial in a four-hour period. This is an example of what kind of sampling?
Correct Answer
A. Cluster
Explanation
The given sampling method, where we randomly select several television channels and sample every commercial in a four-hour period, is an example of cluster sampling. In cluster sampling, the population is divided into groups or clusters, and a random sample of clusters is selected. In this case, the television channels act as the clusters, and we randomly select a few channels to study all the commercials aired during a specific time period. This method is often used when it is not feasible or practical to sample individuals directly.
5.
To study attitudes on the school budget, we will ask people their opinons at back to school night. This is an example of what kind of sampling?
Correct Answer
B. Convenience
Explanation
This is an example of convenience sampling because the researcher is selecting participants based on their availability and convenience. By asking people their opinions at back to school night, the researcher is choosing individuals who are easily accessible and present at that specific event. Convenience sampling is often used when it is difficult or impractical to select a random sample, but it may introduce bias as it may not represent the entire population accurately.
6.
To say a sample is biased means the sample does not represent the population
Correct Answer
A. True
Explanation
If a sample is biased, it means that it does not accurately represent the entire population. This could be due to various factors such as selecting a sample that is not random or representative of the population. Bias in a sample can lead to inaccurate conclusions and generalizations about the population as a whole. Therefore, the statement that a biased sample does not represent the population is true.
7.
To study attitudes on the school budget, we will ask people their opinons at back to school night. Describe the potential bias in our sample
8.
2000 people in a simple random sample were sent surveys on their eating habits; 317 return their survey. Describe the potential bias in this response rate.
9.
What are the two conditions under which a sample scheme can be considered a simple random sample.
10.
From the following web page: http://www.nationsonline.org/oneworld/country_code_list.htm, select four countries at random by using your random number table to select ISO numeric codes. Note that you can sort the list by code.
11.
What are some shape characteristics we would look for in a graph? (Check all that apply.)
Correct Answer(s)
A. Skewed
B. Uniform
Explanation
In graph analysis, we look for shape characteristics that can provide insights into the data. Skewed refers to a graph that is not symmetrical and has a long tail on one side. This can indicate an uneven distribution of data. Uniform refers to a graph that has an equal distribution of data points, indicating a consistent pattern. Linear refers to a graph that shows a straight line, indicating a constant rate of change. Exponential refers to a graph that shows rapid growth or decay. Quadratic refers to a graph that shows a parabolic shape, indicating a relationship involving squares.
12.
A gap in a quantitative plot suggest one of the following.
Correct Answer
A. The boundary between two populations
Explanation
A gap in a quantitative plot suggests the presence of two distinct populations. This means that there is a clear separation or difference between two groups of data points. It could indicate that there are two distinct categories or groups being represented in the data, and the gap represents the boundary between these populations. This could be due to factors such as different demographics, characteristics, or variables that are being measured.
13.
In a two-way frequency table, marginal distributiion refers to
Correct Answer
C. The sums of the rows and columns
Explanation
The marginal distribution in a two-way frequency table refers to the sums of the rows and columns. It provides the total count or proportion of each category in the table, allowing for analysis of the distribution of variables individually. By summing the frequencies in each row and column, we can determine the overall distribution of each variable separately, without considering the relationship between the variables.
14.
To study car safety, we will collect data on car accidents from the first 10 body shops listed in the phone book. 1) Why is this not a simple random sample? 2) What kind of sample is it, and 3) What is the potential bias?
15.
We would like to study the safety of automobiles by collecting data on the severity of injuries sustained in automobile accidents. What is the population for this study?
Correct Answer
A. Automobiles
Explanation
The population for this study refers to the group of entities or individuals that the researchers are interested in studying. In this case, the question asks about the safety of automobiles, so the population for this study would be automobiles themselves. The researchers want to collect data on the severity of injuries sustained in automobile accidents, which would involve studying the automobiles and the accidents they are involved in. Accident victims, on the other hand, would be the sample or subset of the population that the researchers would collect data from.
16.
What is the page number of your random number table?