Exam 9: Do the Numbers Make Sense

A 500-point drop in the DJIA was a big drop when the DJIA was at 2246 in October of 1987 and a much smaller drop when the DJIA reached 11,421 in September of 2008. The percent by which stock prices fall is a more meaningful measure. The lesson here is that

A student reports that, of a simple random sample of 50 college undergraduate students, 21% were taking more than fifteen credit hours. We know that the student has made a mistake (or maybe really did not conduct the survey). Why?

Before starting a body building program, Joe weighed 185 pounds. At the end of the program, he weighed 202 pounds. This is a percentage gain of:

In the last half of 2015, the price of Apple, Inc. (AAPL) common stock dropped from $126.60 per share to $105.26 per share. What percent decrease is this?

Following are data on the populations and numbers of death row prisoners for several states. Which state has the highest number of death row prisoners relative to the size of its population?

Which of the following statements do you think could possibly be true?

In 1989, 2.0 billion cigars were smoked in the United States. In 2015, 2.4 billion cigars were smoked. What percentage change is this?

A newspaper reported that a state agency had reduced its workforce by 15% from 80,000 employees to

The average wage of production workers (adjusted for the effects of inflation) was $11.08 an hour in 1981 and $10.35 an hour in 1991. In the decade of the 1980s, wages went down by about

A web page headline said, "Winter Storm Jonas Slams the East Coast-Airline Cancels All But 0.1 Percent, or 62, Out of the Scheduled 6000 Flights." The correct percentage canceled was:

An ad for a new mouth rinse says that it "reduces plaque on teeth by 200%." What does this mean?

The net asset value of a mutual fund has decreased from $2,700 on December 31 to $1,330 now. The percent decrease in value is about:

Michelle's income two years ago was $220,000. Last year, her income was $300,000. The percent change in Michelle's income was:

A recent warning from a neighborhood watch group stated that about 29% of all home break-ins occur over the weekend (Saturday and Sunday), so residents should be especially vigilant on weekends.

A student reports that, of a simple random sample of 25 college undergraduate students, 18% were working at least two jobs. We know that the student has made a mistake (or maybe really did not conduct the survey). Why?

The price of gold was $1061 per ounce on December 31 and has risen 14.78 percent since that time. What is the price per ounce now?

From 2010 to 2015, the average annual profit for Acme Floormat Company has increased from $1.5 million to $10 million.

The Dow Jones Industrial Average (DJIA) is the most common measure of stock market prices. Suppose that the DJIA starts at 17,149 points and drops 500 points. This is a decrease of:

An ad for a new heartburn treatment says that it "reduces heartburn by 300%." What does this mean?

According to the FBI Uniform Crime Report, the robbery rate in the United States is 202 per 100,000 people. At that rate, how many robberies would there be in a state the size of Indiana (5.8 million people)?