The cost to mail a first-class letter within the United States is a function
of its weight. In 2014, the cost was $0.49 for the first ounce and $0.21 for
each additional ounce. Fractions of an ounce are ROUNDED UP to the
nearest ounce. The cost of mailing a letter is described by the function
below. In the function, represents the weight of the letter, rounded up to
the nearest ounce. What is the cost of mailing a first-class letter that
weighs 4.2 ounces?

f(w) = 0.49 +0.21(w - 1)

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?