What does it mean when there is no coefficient of the variable?

a.) there is an error in the equation
b.) the coefficient is zero
c.) the implied coefficient is 1
d.) the coefficient is negative

The answer is C - The implied coefficient is 1. 

The coefficient of a term is the number that comes before the variable. in this case, when there is no coefficient, it is understood that that the coefficient of the variable is equal to 1. Examples are x, y , z, a, etc. Hence the answer to this problem is C.

The major difference is that a histogram is only used to plot the frequency of score occurrences in a continuous data set that has been divided into classes, called bins.  bar charts, on the other hand, can be used for a great deal of other types ofvariables  including  ordinal  andnominal  data sets.