One method for measuring air pollution is to measure the concentration of carbon monoxide, or CO, in the air. Suppose Nina, an environmental scientist, wishes to estimate the CO concentration in Kiev, Ukraine. She randomly selects 40 locations throughout the city measures the CO concentration at each location. Based on her 40 samples, she computes the margin of error for a 95% t-confidence interval for the mean concentration of CO in Kiev, in g/m, to be 4.97. What would happen to the margin of error if Nina decreases the confidence level to 90%? Nina increases the confidence level to 99%? Nina decreases the sample size to 31 locations? Nina increases the sample size to 55 locations? Answer Bank Increase Stay the same Decrease