1. Concept Quiz Ch. 1-3 True/False

2. A primary use of inferential statistics is to make generalizations from a sample to a proportion.
True
False

3. Answer:
True
Statistics is about making inference from a sample to a population. For example, the SAT average for a random sample of 10,000 students should be close to the true population average.

4. The relative frequency for a particular category is the number of times the category appears in the data.
True
False

5. Answer:
b) False
The relative frequency is a percent. The number of times the category appears in the data is just the frequency…not the “relative” frequency.

6. 3. Bar charts should be used only with categorical data.
True
False

7. Answer:
True
Bar charts are for categorical data. Histograms are for quantitative data.

8. A pie chart is most useful for numerical data.
True
False

9. Answer:
b) False
Pie charts are for categorical data only. Think of creating a daily budget. What would be in your pie chart? Food, car, entertainment, college savings, etc. These are categories.

10. 5. A segmented bar chart displays the marginal distribution of a categorical variable.
True
False

11. Answer:
b) False
A segmented bar chart displays the conditional distribution of a categorical variable within each category of another variable.
From the graph above, we can determine from those who allow, 43% percent had success.

12. When collecting data, a number always represents quantitative data.
True
False

13. Answer:
b) False
Think of your student number, this is a categorical variable. A measurement such as height, weight, or age is quantitative. However, even a quantitative variable such as age is categorical if on a survey you are asked in which age group you lie.

14. Based on the graphs below, the variables are considered to be independent.
True
False

15. Answer:
b) False
Remember “independent” means “no association” or “the same.”
Dependent means different. The graphs are different so the variables are dependent meaning there is a relationship between the variables. One does affect the other.

16. 8. Based on the graphs below, the variables are considered to be dependent.

17. Answer:
True
The graphs are different, so there is a dependent relationship between education level and whether a person smokes.

18. Using the table below, a question that would elicit a marginal frequency as an answer would be:
“What percent of students ride the bus to school?”
True
False

19. Answer:
a) True
Marginal frequencies are calculated by either
(row total)/(grand total) or (column total)/(grand total). So, the percent of students who ride the bus to school would be 64/188.

20. A conditional frequency question and answer would be exemplified by the following:
What percent of students ride the bus and are female? The answer would be 34/188.
True
False

21. Answer:
b) False
This is a joint frequency question and answer which is calculated by (bus and female)/(grand total) = 34/188
A conditional frequency question would be, of those who ride the bus, what percent are female. This would be calculated by (bus and female)/(bus total) = 34/64