Arctan(3.4) ≈ 73.6°. You can view the 3.4 as the slope of a line. Then it is clear the the 52.9 and 99.8 can't be right. If you have to do this without a calculator, it can be quite tricky...
4/5n – 1/5 = 2/5n
Add 1/5 to both sides
4/5n = 2/5n + 1/5
Subtract 2/5n from both sides
2/5n = 1/5
Divide both sides by 2/5
n = 1/2
Answer:
1. 30
2. 34
Step-by-step explanation:
2(4(3) + 3)
2(12 + 3)
2(15)
= 30
12(3) - 2
36 - 2
= 34
hope this helps :)
Answer:
(0.0706, 0.1294)
Step-by-step explanation:
Confidence interval of a proportion is:
CI = p ± CV × SE
where p is the proportion,
CV is the critical value (z score or t score),
and SE is the standard error.
The sample is large enough to estimate as normal. For 95% confidence level, CV = z = 1.96.
Standard error for a proportion is:
SE = √(pq/n)
SE = √(0.1 × 0.9 / 400)
SE = 0.015
The confidence interval is:
CI = 0.1 ± (1.96)(0.015)
CI = (0.0706, 0.1294)
Round as needed.
