Q1) Consumer group would like to evaluate average amount of PG&E bill for month of March for single family homes in San Francisco Bay Area. Based on studies conducted in other same climate cities, standard deviation is supposed to be $25. Group would like to evaluate average March bill to be with 5 of population average with 95% level confidence.
Determine the sample size needed.
Q2) If confidence level is increased to 99%, would sample size required increase or decrease?
a) Increase to 166
b) Stays the same
c) Decrease to 58