Let's address each question step by step:
1. Sample Generalization
To determine which sample provides the most valid generalization for the team-building activity preference:
- 400 randomly chosen employees from the list of all employees
- All other options are biased or not representative of the entire employee population.
Most valid sample: 400 randomly chosen employees from the list of all employees.
2. Random Sample of Lamps
To estimate how many of the 12,000 lamps in a 30-story hotel need a new light bulb, the best sampling method for random selection would be:
- 100 lamps on each floor chosen randomly
This ensures that every floor is represented in the sample.
3. Estimating the Number of Patrons Borrowing Novels
If 3 out of 80 patrons borrow novels, then the proportion of patrons borrowing novels can be calculated as:
\[ \text{Proportion} = \frac{3}{80} \]
To find out how many of the 345 patrons borrow novels, we multiply:
\[ \text{Number of patrons} = \frac{3}{80} \times 345 = 12.9375 \] Rounding to the nearest whole number gives us approximately 13 patrons.
4. Mean Times and Differences
To find the mean times each group spent shopping:
-
For Group A: \((18 + 20 + 46 + 34 + 58 + 31 + 41) / 7 = 37.7142857\) (Rounded to 37.7 minutes)
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For Group B: \((15 + 21 + 32 + 42 + 29 + 57 + 39) / 7 = 32.4285714\) (Rounded to 32.4 minutes)
Mean time Group A is 37.7 minutes. Mean time Group B is 32.4 minutes. Difference in mean times: \(37.7 - 32.4 = 5.3\) minutes.
5. Highest Median
To find the highest median:
- Sort and Find Each Median:
- {1, 6, 15, 7, 15, 18, 14} → sorted: {1, 6, 7, 14, 15, 15, 18}; Median is 14.
- {1, 10, 8, 29, 14, 17, 3} → sorted: {1, 3, 8, 10, 14, 17, 29}; Median is 10.
- {11, 15, 16, 8, 12, 14} → sorted: {8, 11, 12, 14, 15, 16}; Median is 13.
- {8, 20, 13, 14, 12, 9} → sorted: {8, 9, 12, 13, 14, 20}; Median is 12.5.
Highest median is 14 from the first data set.
In summary:
- Most valid generalization sample: 400 randomly chosen employees
- Random sample of lamps: 100 lamps on each floor chosen randomly
- Approximate number of patrons borrowing novels: 13 patrons
- Mean shopping times: Group A = 37.7 minutes, Group B = 32.4 minutes, difference = 5.3 minutes
- Data set with the highest median: {1, 6, 15, 7, 15, 18, 14} (Median = 14)