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A residential school stipulates the study hours as 8 : 00 pm to 10 : 30 pm. Warden makes random checks on a certain student 11 occasions a day during the study hours over a period of 10 days and observes that he is studying on 71 occasions. Using 95% confidence interval, the estimated minimum hours of his study during that 10 day period is
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- 8.5 hours
- 13.9 hours
- 16.1 hours
- 18.4 hours
- 8.5 hours
Correct Option: C
Number of total observation in 10 days = 11 × 10 = 110
No. of observation when studying = 71
| ∴ P = | = 0.6455 | |
| 110 |
(Probability of studying)
Total studying hour in 10 days = (2.5 hr) × 10
Hence, Minimum no. of hours of studying in 10 days = (25 hr) × p = 25 × 0.6455 = 16.13 hrs.
