Question

what type of data is found in each column (i.s., categorical [ nominal]; interval [ continuous])?

Answer 1

*Categorical (nominal) data-A nominal variable is one in which values serve only as lables,even if those values are numbers.
eg-when we categorize male and female respondants,we could use a number of 1 for male and 2 for female.However,the values of 1 and 2 in this case do not represent any meaningful order or carry any mathematical meaning.
-They are simply used as lables.Nominal data cannot be used to perform any statistical computations,such as mean and standard deviation,because such statistics do not have any meaning when used with nominal variables.
-However nominal variable can be used to do cross tabulations.
-The chi-square test can be performed on a cross-tabulation of nominal data.

*Interval(continuous) data-For interval variables, we can make arithmetic assumptions about degree of differences between values.
eg-temperature would be the interval variable,we can correctly assume that the differences between 70 and 80 degrees is the same as differences between 80 and 90 degrees.
-However ,the mathematical operations of multiplication and devision do not apply to interval variables.For instance,we cannot accurately say that 100 degrees is twice as hot as 50 degrees..Additionally,interval variables do not have a meaningful zero-point.
-An interval variable can be used to compute commonly used statistical measures such as the average (mean), standard deviation,and the Pearson correlation coefficient.Many other advanced statistical tests and techniques also require interval data.