Exam 1: Introduction to Statistics

A portion or subset of the entities under study is called the statistic.

The basis for inferential statistics is the ability to make decisions about population parameters without having to complete a census of the population.

Sue Taylor, Director of Global Industrial Sales, is concerned by a deteriorating sales trend. Specifically, the number of industrial customers is stable at 1,500, but they are purchasing less each year. She orders her staff to search for causes of the downward trend by selecting a focus group of 40 industrial customers. For this study, the set of 40 industrial customers is ___.

At an international conference on education, delegates were asked to answer the following questions: a) What $\textbf{ country }$ are you from? b) What $\textbf{ distance }$ did you travel to get to the conference? c) What is the $\textbf{ highest level of education }$ you have completed? d) What is your $\textbf{ age? }$ Classify the variables in bold as either quantitative or categorical.

Statistics is commonly divided into two branches called descriptive statistics and summary statistics.

In a survey conducted among 200 first years of a certain college, 36 percent were business majors, 34 percent were science majors, and 23 percent arts majors. a) What constitutes the population? b) What is the sample? c) The 36 percent of the 200 first years who were business majors is?

Sue Taylor, Director of Global Industrial Sales, is concerned by a deteriorating sales trend. Specifically, the number of customers is stable at 1,500, but they are purchasing less each year. She orders her staff to search for causes of the downward trend by surveying all 1,500 industrial customers. Sue is ordering a ___.

A descriptive measure of the population is called a parameter.

A new sales person is paid a commission on each sale. This person made $2,000 his first month on the job. From this he concludes that he will make $24,000 during his first year. This is an example of ___.

On discovering an improperly adjusted drill press, Jack Joyner, Director of Quality Control, ordered an inspection of every fifth casting drilled during the evening shift. Jack is ordering a ___.

Using data from a group to generalize to a larger group involves the use of ___.

On discovering an improperly adjusted drill press, Jack Joyner, Director of Quality Control, ordered a 100% inspection of all castings drilled during the evening shift. Jack is ordering a ___.

A local manufacturing plant randomly selected 200 items from a production run and 9 of them are defective. The proportion of defective items in this sample is a ___.

A researcher wants to know what the average variation is in altimeters of small, privately owned airplanes. The task of determining this is expensive and time consuming, if even possible, given the large number of such airplanes. The researcher decides to use government records to randomly locate the owners of ten such planes and then get permission to test the altimeters. When the researcher is done, he will use the data gathered from the group of ten to reach conclusions about all small, privately owned airplanes. This process can best be described as ___.

You are the owner of a camping site that has a small pond with fishes, and you want to know approximately the number of fishes currently in the pond. For this purpose, you catch 30 fishes and mark them with a special ink that will take a few days to be washed away. The ink doesn't affect the fishes in any way. The fishes are returned promptly to the pond after being marked. The next day at the same time of day you return and catch 30 fishes, and you find out that 5 of these fishes are marked.

A market researcher is interested in determining the average income for families in Duval County, Florida. To accomplish this, she takes a random sample of 400 families from the county and uses the data gathered from them to estimate the average income for families of the entire county. This process is an example of ___.

One of the main ways to organize the study of statistics is to divide it in two branches. These two branches are ___ statistics and ___ statistics.

You are the owner of a camping site and want to estimate the average age of your customers. For this purpose, you select a representative sample of your clients and offer them a discount good for their next visit as compensation for filling out a short questionnaire that includes relevant age intervals. The average age of the customers who fill out the questionnaire is

Calculation of population parameters is usually either impossible or excessively time consuming and costly.

A descriptive measure of the sample is called a statistic.