Introductory Statistics: Chapter 1 and 2 Key Concepts
Termini in questo insieme (26)
Statistics is the science of collecting, analyzing, interpreting, presenting, and organizing data.
A parameter is a numerical value that describes a characteristic of a population.
A statistic is a numerical value that describes a characteristic of a sample.
Variables are characteristics or attributes that can assume different values.
The levels are Nominal, Ordinal, Interval, and Ratio, which classify data based on their nature and the mathematical operations allowed.
A lurking variable is an unobserved variable that influences the relationship between the studied variables.
Cluster sampling divides the population into clusters, then randomly selects entire clusters for the sample.
Stratified sampling divides the population into strata, then randomly samples from each stratum proportionally.
Bias is a systematic error that causes the sample to misrepresent the population.
Skew describes the asymmetry of a distribution; it can be left (negative) or right (positive) skewed.
A parameter describes a population, while a statistic describes a sample.
Discrete variables have countable values; continuous variables can take any value within a range.
Qualitative variables describe categories; quantitative variables represent numerical values.
Nominal data are categories without order or ranking.
Ordinal data have categories with a meaningful order but no consistent difference between ranks.
Interval data have ordered categories with equal intervals but no true zero point.
Ratio data have ordered categories, equal intervals, and a true zero point.
An experiment involves manipulating variables; an observation involves measuring without intervention.
k = population size ÷ sample size; it determines the interval for selecting samples.
Response bias occurs when participants answer questions untruthfully or inaccurately.
Nonresponse bias occurs when some selected individuals do not respond, skewing results.
Sampling bias happens when the sample is not representative of the population.
List data values and count how often each occurs.
A distribution showing the proportion or percentage of each data value relative to the total.
A bar graph representing frequencies of discrete data values.
Analyze data points plotted over time to identify trends and percent changes.