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 Zagreb, Croatia. She randomly selects 45 locations throughout the city measures the CO concentration at each location. Based on her 45 samples, she computes the margin of error for a 95% t-confidence interval for the mean concentration of CO in Zagreb, in µg/m³, to be 4.28. 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 33 locations? Nina increases the sample size to 65 locations? Answer Bank Increase Stay the same Decrease

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