Self-Check 1.3, 1.4
- Page ID
- 36452
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Name:___________________________________Date:__________________Row:___________
Self-Check 1.3, 1.4
1. What type of measure scale is being used? Nominal, ordinal, interval or ratio.
a. Political outlook: extreme left, left-of-center, right-of-center, extreme right
b. Time of day on an analog watch
c. The distance in miles to the closest grocery store
d. The dates 1066, 1492, 1644, 1947, and 1944
e. The heights of 21–65 year-old women
f. Common letter grades: A, B, C, D, and F
2. The table shows the amounts, in inches, of annual rainfall in a sample of towns.
| Rainfall (Inches) | Frequency | Relative Frequency | Cumulative Relative Frequency |
| 2.95–4.97 | 6 | 6/50 = 0.12 | 0.12 |
| 4.97–6.99 | 7 | 7/50 = 0.14 | 0.12 + 0.14 = 0.26 |
| 6.99–9.01 | 15 | 15/50 = 0/30 | 0.26 + 0.30 = 0.56 |
| 9.01–11.03 | 8 | 8/50 = 0.16 | 0.56 + 0.16 = 0.72 |
| 11.03–13.05 | 9 | 9/50 = 0.18 | 0.72 + 0.18 = 0.90 |
| 13.05–15.07 | 5 | 5/50 = 0.10 | 0.90 + 0.10 = 1.00 |
| Total = 50 | Total = 1.00 |
a. Find the percentage of rainfall that is less than 9.01 inches.
b. Find the percentage of rainfall that is between 6.99 and 13.05 inches.
c. Find the number of towns that have rainfall between 2.95 and 9.01 inches.
d. What fraction of towns surveyed get between 11.03 and 13.05 inches of rainfall each year?
3. Fifty part-time students were asked how many courses they were taking this term. The (incomplete) results are shown below:
| # of Courses | Frequency | Relative Frequency | Cumulative Relative Frequency |
| 1 | 30 | 0.6 | |
| 2 | 15 | ||
| 3 |
a. Fill in the blanks in the table above.
b. What percent of students take exactly two courses?
c. What percent of students take one or two courses?
4. You are concerned about the effects of texting on driving performance. Design a study to test the response time of drivers while texting and while driving only. How many seconds does it take for a driver to respond when a leading car hits the brakes?
a. Describe the explanatory and response variables in the study.
b. What are the treatments?
c. What should you consider when selecting participants?
d. Your research partner wants to divide participants randomly into two groups: one to drive without distraction and one to text and drive simultaneously. Is this a good idea? Why or why not?
e. Identify any lurking variables that could interfere with this study.
f. How can blinding be used in this study?