#serial-dependence

Question 1: Single choice

Two series are generated by target = w * lag_1 + error, where lag_1 is the previous value and error is random noise: one with $w = 0.95$ , the other with $w = -0.95$ . What does the series with $w = -0.95$ look like in a time plot?

It zig-zags, since consecutive values tend to have opposite signs1
It stays above or below zero for long runs before crossing over2
It trends steadily downward, because the weight is negative3
It looks like pure noise, because the previous value carries no information4

Timed test