Cody summer sells tires for tractor trailers. he earns 4.5% commission on the first $6,000 in sales, 8% commission on the next $6,000, and 12% commission on sales over $12,000. last month he sold $18,000 worth of tires. what was his total commission?

Recall that the owner of a local health food store recently started a new ad campaign to attract more business and wants to know if average daily sales have increased. historically average daily sales were approximately $2,700. the upper bound of the 95% range of likely sample means for this one-sided test is approximately $2,843.44. if the owner took a random sample of forty-five days and found that daily average sales were now $2,984, what can she conclude at the 95% confidence level?