1. An accounting firm measured the blood pressures of ten of its certified public accountants (CPAs) before and during the spring 1996 tax season. The systolic pressure for the ten individuals, designated A through J, were as follows:

	A	B	C	D	E	F	G	H	I	J
Before	110	124	98	105	115	120	118	110	123	95
During	115	126	97	108	115	124	119	113	121	96

Is there sufficient evidence that blood pressure rises for CPAs during tax season?

2. Polychlorinated biphenyl (PCB) contamination of a river by a manufacturer is being measured by amounts of the pollutant found in fish. A company scientist claims that the fish contain only 5 parts per million, but an investigator believes the figure is higher. Suppose a random sample of six fish revealed the following levels of PCB: 6.8, 5.6, 5.2, 4.7, 6.3, and 5.4. Is there sufficient evidence that the fish are contaminated above the stated level?

3. An employer wishes to compare typing speeds of graduates from two different study programs. A random sample of eight graduates from the first course type at: 62, 85, 59, 64, 73, 70, 75, and 72 words per minute. A random sample of six graduates from the second course type at: 75, 64, 81, 55, 69, and 58 words per minute. Should the employer conclude that one program is better than the other?

4. Suppose that your rival in the marketing department has what you consider a dumb idea. Your boss, who knows nothing about statistics, is relatively conservative but will follow up on this dumb idea if there is good evidence that more than 25% of his customers like it. A random survey of 40 customers is taken and 12 of them favor the idea. Your rival, capable of sixth grade math, points out that 12/40 = 30%. Perform the significance test and explain to your boss why this data is not strong evidence that more than 25% like the idea.