Consider an MA(1) process:
x_t = ω_t + θω_t-1,
where θ is a parameter.
(a) Derive a formula for the power spectrum of x_t, expressed in terms of θ and ω.
(b) Use arma. spec() to plot the spectral density of x_t for θ > 0 and for θ < 0 (just select arbitrary values).
(c) How should we interpret the spectra exhibited in part (b)?

The measure of one angle of an octagon is two times smaller that of the other seven angles. what is the measure of each angle?

Dexter read 11 science fiction books and 5 history books. lena read 9 science fiction books and 4 history books. compare the students’ ratios of science fiction books to history books. 1. determine the ratios’ form:    science fiction books to history books 2. write the ratios as fractions:    dexter: 115; lena: 94 3. rewrite with a common denominator. 4. compare. 5. answer the question. determine which shows the correct comparison of the ratios for this problem.

Select the number of ways in which a line and a circle can intersect