• Experiments on learning in animals sometimes measure how long it takes a mouse to find its way through a maze. The mean time is 20 seconds for one particular maze. A researcher thinks that playing rap music will cause the mice to complete the maze faster. She measures how long each of 12 mice takes with the rap music as a stimulus.

24, 16, 17, 20, 20, 21, 28, 25, 15, 10, 16, 15

• Self efficacy is a general concept that measures how well we think we can control different situations. Participants in a study were asked, “How sure are you that you can eat foods low in fat over the next month?” One group of 165 received intervention, and an average score of 4.1 with a 1.19 sample standard deviation. Another group of 212 received no intervention and scored 3.67 with a 1.12 sample standard deviation.

• A study of income among internet users found that 493 reported income of less than $50,000, while 378 reported an income greater than $50,000. For nonusers, the corresponding numbers were 477 and 200.

• A dual X-ray absorptiometry (DXA) scanner is used to measure bone mineral density for people who may be at risk for osteoporosis. To be sure that the measurements are accurate, an object called a “phantom” that has known mineral density µ = 1.3 and σ = 0.04 grams per square centimeter is measured. This phantom is scanned 8 times.

1.33, 1.32, 1.41, 1.36, 1.29, 1.35, 1.43, 1.28

• An automobile manufacturer would like to know what proportion of its customers are dissatisfied with the service received from their local dealer. From past studies, they believe that this proportion will be about 25%. Data shows that 116 of 387 sampled are dissatified.

• Children in different age groups were compared on their ability to sort new products into the correct category. 50 kids ages 4-5 had 20 which were able to sort correctly. 53 kids ages 6-7 had 28 which were able to sort correctly.

3 bedrooms vs. 4 bedrooms

• Prices in thousands of dollars• 4 bedrooms

121.9, 139.9, 157, 159.9, 176.9 224.9, 235, 245, 294

• 3 bedrooms

65.5, 79.9, 79.9, 79.9, 82.9, 87.9, 94, 97.5, 105, 111.9, 116.9, 117.9, 119.9, 122.9, 124, 125, 126.9, 127.9, 127.9, 127.9, 132.9, 145, 145.5, 157.5, 194, 205.9, 259.9, 265

• The researchers studying vitamin C were also interested in a similar commodity called wheat soy blend (WSB). Both of these commodities are mixed with other ingredients and cooked. Loss of vitamin C as a result of this process was another concern of the researchers. One preparation used in Haiti called gruel can be made from WSB, salt, sugar, milk, banana, and other optional items to improve taste. Samples of gruel prepared in Haitian households were collected. The vitamin C content was measured before and after cooking. Here is the data:

Sample 1 2 3 4 5

Before 73 79 86 88 78

After 20 27 29 36 17

• A manufacturer of electric motors tests insulation at high temperature (250 C) and records the number of hours until the insulation fails. The data for 5 specimens are:

446 326 372 377 310

• In a random sample of 975 students from a large public university, it was found that 463 of the students changed majors during their college years.

• “Conservationists have despaired over destruction of tropical rainforest by logging, clearing, and burning.” These words begin a report on a statistical study of the effects of logging in Borneo. Data on the number of trees species in 12 unlogged forest plots and 9 similar plots logged 8 years earlier were recorded.

• Unlogged– 22 18 22 20 15 21 13 13 19 13 19 15• Logged– 17 4 18 14 18 15 15 10 12

• The number of drivers who use seat belts depends on things like age and gender. It also depends on the local law. In New York City, police can stop a driver who is not belted. In Boston, police can cite a driver for not wearing a seat blet only if the driver has been stopped for some other violation. From a random sample of female Hispanic drivers, From New York, of the 220 drivers, 183 were belted. For Boston, only 68 of the 117 drivers were belted.