week 2 Flashcards
What is a variable?
any characteristic that differs among individuals
What is Categorical variable?
Categorical variable describe membership to a group are qualitative not quantitative. characteristics and do not have a magnitude orn a numerical scale.
What is a numerical data?
are quantitative measurements that have magnitude on a numerical scale.
is age at death numerical or categorical?
numerical
are size classes numerical or categorical?
categorical
is number of mates numerical or categorical?
numerical
What is an explanatory variable?
The variable that predicts or affects the response variable. Is the one manipulated by the researcher.
What is the response variable?
measured effect of the treatment
What are descriptive statistics or summary statistics?
quantities that capture important features of frequency distributions(Standard deviation, mean)
What is the most important descriptive statistics for categorical variables?
the proportion
What do the most important descriptive statistics do?
measure the:
location
spread
of a frequency distribution
What is the sample mean?
The average of the measurements in the sample, the sum of all observations divided by the number of observations(n).
What does the standard deviation measure?
the spread of a distribution. It indicates just how different measurements typically are from the mean.
What is the mean?
the middle measurement of a set of observations
What is the interquartile range?
The difference between the third and first quartiles of the data. It is the span of the middle 50% of the data.
