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