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1.1 Definition of Statistics, Probability and Key Terms (4/16/2025)

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17 questions
1.1 Definitions of Statistics, Probability, and Key Terms
The science of statistics deals with the collection, analysis, interpretation, and presentation of data. We see and use data in our everyday lives.
1

How many hours of sleep do you get on average?

1
Probability is the study of randomness


Example is a fair coin toss
1
1

Does your dot plot look the same as or different from the example? Why? If you did the same example in an English class with the same number of students, do you think the results would be the same? Why or why not?

Where do your data appear to cluster? How might you interpret the clustering?

Vocabulary

Key terms


Populations- Collection of persons, things, or objects under study
Sample- Select a portion or subset of the larger population and study that portion to gain information of the larger population
Parameter- Is a numerical characteristics of the whole population
Statistic- Is a number that represents a property of the sample
Variable- a characteristic or measurement that can be determined for each member of the population.
Data- Data are the actual values of the variable. They may be numbers of they may be words. (Datum is a single value)
Numerical- values with equal units such as weight in points or time in hours
Categorical- places a person in a category ( may get tricky when numbers represent rankings or placings)

Common Terms

Mean- When you add up the terms and divide the the amount of terms

ie Math scores of 86,75 and 92 are added up and divide by three to get 84.3 rounded

Proportion- When you take a divide the number of interest by the total number of a population or sample

ie if I have 30 students and 18 passed the exam, then \frac{18}{30} passed.
Practice with the vocabulary
1
Determine what the key terms refer to in the following study. We want to know the average (mean) amount of money first year college students spend at ABC College on school supplies that do not include books. We randomly surveyed 100 first year students at the college. Three of those students spent $150, $200, and $225, respectively.

Population: _______
Sample: _______
Parameter: _______
Statistic:_______
Variable: _______
Data: _______
1

Determine the key terms refer to in the following study

A study was conducted at a local college to analyze the average cumulative GPA’s of students who graduated last year. Fill in the letter of the phrase that best describes each of the items below.

Draggable itemCorresponding Item
Not Specific Enough
all students who graduated from the college last year
Variable
the average cumulative GPA of students in the study who graduated from the college last year
Population
the average cumulative GPA of students who graduated from the college last year
Sample
a group of students who graduated from the college last year, randomly selected
Statistic
the cumulative GPA of one student who graduated from the college last year
Parameter
3.65, 2.80, 1.50, 3.90
Data
all students who attended the college last year
1
Determine what the key terms refer to the following study.

As part of a study designed to test the safety of electric automobiles, the National Transportation Safety Board collected and reviewed data about the effects of a crash on test dummies. Here is the criterion they used:




Population- _______
Sample- _______
Parameter- _______
Statistic- _______
Variable- _______
Data- _______
1
Determine what the key terms refer to in the following study.

An insurance company would like to determine the proportion of all medical doctors who have been involved in one or more malpractice lawsuits. The company selects 500 doctors at random from a professional directory and determines the number in the sample who have been involved in a malpractice lawsuit.

Population- _______
Sample- _______
Parameter- _______
Statistic- _______
Variable- _______
Data- _______
Practice
1
Determine what the key terms refer to in the following study.

Ski resorts are interested in the mean age that children take their first ski and snowboard lessons. They need this information to plan their ski classes optimally.

Population- _______
Sample- _______
Parameter- _______
Statistic- _______
Variable- _______
Data- _______
1
Determine what the key terms refer to in the following study.

Insurance companies are interested in the mean health costs each year of their clients, so that they can determine the costs of health insurance.

Population- _______
Sample- _______
Parameter- _______
Statistic- _______
Variable- _______
Data- _______
1
Determine what the key terms refer to in the following study.

A marriage counselor is interested in the proportion of clients they counsel who stay married.

Population- _______
Sample- _______
Parameter- _______
Statistic- _______
Variable- _______
Data- _______
1
Determine what the key terms refer to in the following study.

A marketing company is interested in the proportion of people who will buy a particular product.

Population- _______
Sample- _______
Parameter- _______
Statistic- _______
Variable- _______
Data- _______
A Lake Tahoe Community College instructor is interested in the mean number of days Lake Tahoe Community College math students are absent from class during a quarter.
1

What is the population she is interested in?

1

Consider the following:

X = number of days a Lake Tahoe Community College math student is absent

In this case, X is an example of a:

1

The instructor's sample produces a mean number of days of 3.5 days. This value is an example of

1

What questions would you like to ask of Alisal High School students?

1

What questions would you like to ask of Alisal High School students that is measurable?