Exam 1: The Nature of Statistics

List all possible samples from the specified population. -The members of a board of directors have the following roles: president (P), vice president (V), secretary (S), treasury (T), and fundraiser (F). Consider these board members to be a population of Interest. List the 10 possible samples (without replacement)of size two from this population of five Board members.

A computer network manager wants to test the reliability of some new and expensive fiber-optic Ethernet cables that the computer department just received. The computer department received 7 Boxes containing 50 cables each. The manager does not have the time to test every cable in each Box. The manager will choose one box at random and test 10 cables chosen randomly within that Box. What is the population?

Identify the study as an observational study or a designed experiment. -In a group of 500 men and women, those who smoked did worse on tests of reaction time than those who did not smoke.

A herpetologist performed a study on the effects of the body type and mating call of the male bullfrog as signals of quality to mates. Four life-sized dummies of male bullfrogs and two sound Recordings provided a tool for testing female response to the unfamiliar frogs whose bodies varied By size (large or small)and color (dark or light)and whose mating calls varied by pitch (high,Normal, or low). The female bullfrogs were observed to see whether they approached each of the Four life-sized dummies. Identify the treatments.

An education researcher wishes to assess the effectiveness of three different methods for teaching young children to read. The 380 children participating in the study are divided into three groups. The study runs for six months. The children in the first group are taught using method A, the children in the second group are taught using method B, and the children in the third group are taught using method C. At the end of the six months, the reading ability of the children in the different groups is assessed. Why might randomization be used when dividing the children into three groups?

Identify the study as an observational study or a designed experiment. -In a clinical trial, 780 participants suffering from high blood pressure were randomly assigned to one of three groups. Over a one-month period, the first group received the experimental drug, the Second group received a placebo, and the third group received no treatment. The diastolic blood Pressure of each participant was measured at the beginning and at the end of the period and the Change in blood pressure was recorded. The average change in blood pressure was calculated for Each of the three groups and the three averages were compared.

Explain the difference between an observational study and a designed experiment.

Before premiering a blockbuster movie at a theater, test screenings are done beforehand. A small number of selected theaters are chosen geographically throughout the country. Each theater chosen Is supposed to be representative of theatergoers in that area. Everyone is interviewed when the Movie is over. Identify the type of sampling used in this example.

A designed experiment is described. Identify the specified element of the experiment. -A herpetologist performed a study on the effects of the body type and mating call of the male bullfrog as signals of quality to mates. Four life-sized dummies of male bullfrogs and two sound Recordings provided a tool for testing female response to the unfamiliar frogs whose bodies varied By size (large or small)and color (dark or light)and whose mating calls varied by pitch (high, Normal, or low). The female bullfrogs were observed to see whether they approached each of the Four life-sized dummies. Identify the response variable.

Identify the study as an observational study or a designed experiment. -A doctor performs several diagnostic tests to determine the reason for a patient's illness.

An education researcher was interested in examining the effect of the teaching method and the effect of the particular teacher on students' scores on a reading test. In a study, there are four Different teachers (Juliana, Felix, Sonia, and Helen)and three different teaching methods (method A, method B, and method C). The number of students participating in the study is 258. Students are randomly assigned to a teaching method and teacher. Identify the experimental units (subjects).

Provide an appropriate response. -From a group of 496 students, every 49th student starting with the 3rd student is selected. Identify the type of sampling used in this example.

A designed experiment is described. Identify the specified element of the experiment. -A herpetologist performed a study on the effects of the body type and mating call of the male bullfrog as signals of quality to mates. Four life-sized dummies of male bullfrogs and two sound Recordings provided a tool for testing female response to the unfamiliar frogs whose bodies varied By size (large or small)and color (dark or light)and whose mating calls varied by pitch (high, Normal, or low). The female bullfrogs were observed to see whether they approached each of the Four life-sized dummies. Identify the experimental units.

A herpetologist performed a study on the effects of the body type and mating call of the male bullfrog as signals of quality to mates. Four life-sized dummies of male bullfrogs and two sound Recordings provided a tool for testing female response to the unfamiliar frogs whose bodies varied By size (large or small)and color (dark or light)and whose mating calls varied by pitch (high, Normal, or low). The female bullfrogs were observed to see whether they approached each of the Four life-sized dummies. Identify the levels of each factor.

The table below shows the number of homicides in the U.S. in each of the years 1989-1993. Murder and non-negligent manslaughter Year Number of offenses 1989 21,500 1990 23,440 1991 24,700 1992 23,760 1993 24,530 Classify the study as either descriptive or inferential.

Several watch-dog consumer groups have criticized the fast food industry for serving food with excessive fat content. One watch-dog announced that it will randomly select one fast food chain Per week. The watch-dog will then decide, as a group, to purchase one item off the menu that has Been advertised the most on television and in the newspapers. The watch-dog will then have that Heavily-advertised, just-purchased item professionally sampled for fat content. Weekly results Will be posted on the watch-dog's website. For this scenario, what best describes the watch-dog's Sampling activities each week?

Provide an appropriate response. -Define simple random sampling. Explain why this is important in design of experiments.

At a college there are 120 freshmen, 90 sophomores, 110 juniors, and 80 seniors. A school administrator selects a simple random sample of 12 of the freshmen, a simple random sample of 9 Of the sophomores, a simple random sample of 11 of the juniors, and a simple random sample of 8 Of the seniors. She then interviews all the students selected. Identify the type of sampling used in This example.

An education researcher was interested in examining the effect of the teaching method and the effect of the particular teacher on students' scores on a reading test. In a study, there are four Different teachers (Juliana, Felix, Sonia, and Helen)and three different teaching methods (method A, method B, and method C ). The number of students participating in the study is 258. Students are randomly assigned to a teaching method and teacher. Identify the response variable.

The two major types of statistics are ______________ statistics and ___________ statistics.