The last 2 options are correct
This is the best i could find
9514 1404 393
Answer:
1 -√2
Step-by-step explanation:

tan(7π/8) = 1 -√2
Answer:
Mean = 1.9
Standard deviation = 0.6
Step-by-step explanation:
The Mean is calculate by the formula:

⇒ 
Thus Mean to the nearest tenth is 1.9
Standard Deviation is the square root of sum of square of the distance of observation from the mean.
where,
is mean of the distribution.
Putting all values in the formula, We get
Standard Deviation = 0.597 ≈ 0.6