The directrix of a parabola is x = 4. Its focus is (2,6).
2 answers:
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Answer:
95% of the population spent between 16.8 hours to 26.2 hours on social media per month
Step-by-step explanation:
- subtracting 1 from sample size: 83-1= 82
- Note Mean=21.5 and standard deviation=2.5
- Subtracting confidence interval from 1 and dividing by 2: (1-0.95)/2=0.025
- At α=0.025 and dF=82, the t-distribution table gives 1.984
- Divide standard deviation by square root of sample size: 21.5/√83= 2.36
- Multiplying answer in step 4 by answer in step 5: 2.36×1.984= 4.68
- For lower end: 21.5-4.68= 16.82
- for upper end: 21.5+4.68=26.18
