PLEASE HELP What are the phase shift and period for the function y equals two cosine start fraction one over two end fraction left parenthesis theta plus thirty degrees end power right parenthesis minus four question mark (4 points) Phase shift: 30° left, period: 720°
Phase shift: 30° right, period: 330°
Phase shift: 30° right, period: 90°
Phase shift: 30° left, period: 180°

1) a researcher is studying a population of bats in which 16% of the population has a certain trait. the researcher wants sampling distribution with a standard deviation that is less than 2%. which sample sizes could the researcher use? select all that apply : a)n=200 b) n=300 c) n=400 d) n=500 2) from a normal distribution population, a simple random sample of size 38 is taken. the mean of the sample is 82 and the standard deviation of the sample is 4. what is the 90% confidence interval for the population mean? round to the nearest tenth ( [1], 83.1)