Stats test 1

descriptive statistics

describes data

discrete variable

has finite number of possible values or countable number of possible values

continuous va

has infinite number of possible values and are measured by the level of accuracy

Parameter

is a numerical summary of a population.

statistic

is a numerical summary of a sample.

cluster sample

is obtained by dividing the population into groups and selecting all individuals from within a random sample of the groups.

stratified sample

is obtained by dividing the population into homogeneous groups and randomly selecting individuals from each group.

qualitative variable

numerical measurement of individuals

random sampling

process of using chance to select individuals

interferential statistics

take results from sample and extend onto population

If percentages are​ used, the sum should be​ 100%. If proportions are​ used, the sum should be 1.

After constructing a relative frequency distribution summarizing IQ scores of college​ students, what should be the sum of the relative​ frequencies?

The standard deviation is the positive square root of the variance. The standard deviation and variance can never be negative. Squared deviations can never be negative.

Explain the relationship between variance and standard deviation. Can either of these measures be​ negative? Explain.

False. In a frequency​ distribution, the class width is the distance between the lower or upper limits of consecutive classes.

In a frequency​ distribution, the class width is the distance between the lower and upper limits of a class.

lower upper

The​ ______ class limit is the smallest value within the class and the​ ______ class limit is the largest value within the class.

class width

The​ _________________ is the difference between consecutive lower class limits.In a frequency​ distribution, the class width is the distance between the lower and upper limits of a class.

Relative frequency of a class is the percentage of the data that falls in that​ class, while cumulative frequency of a class is the sum of the frequencies of that class and all previous classes.

What is the difference between relative frequency and cumulative​ frequency?

Descriptive statistics

Which branch of statistics deals with the organization and summarization of collected​ information?

Statistics is used to answer questions with​ 100% certainty.

Which of the following is not true of​ statistics?

qualitative or categorical variables

classification of individuals based on some attribute or characteristic