Which of the following are true statements?
i. both dotplots and stemplots can show symmetry, gaps, clusters, and outliers.
ii. in histograms, relative areas correspond to relative frequencies.
iii. in histograms, frequencies can be determined from relative heights.

I and II.

Step-by-step explanation:

Dot plots are charts that represent data points on a simple scale using filled circles. Stemplots allow plotting data by dividing it into stems (largest digit) and leaves (smallest digits). Both dot plots and stemplots are like histograms since they allow to compare data relating to only one variable, and are used for continuous, quantitive data, highlighting gaps, clusters, and outliers.    

Histograms use bars to represents amounts, with no space between the bars and the height of the bars is proportional to the frequency or relative frequency of the represented amount. We refer to the relative frequency of a case when this frequency is divided by the sum of all frequencies of the cases. The proportionality between the height of the bar and the frequency is right when the width (interval) of the bar is the same for everyone, on the contrary, the area of the bar would be proportional to the frequency of cases.      

Therefore, of all the above, the correct statements are I and II. Statement III is incorrect because relative heights are proportional to relative frequencies.        

I hope it helps you!                    

in problems involving proportions, we can use cross products to test whether two ratios are equal and form a proportion. to find the cross products of a proportion, we multiply the outer terms, called the extremes, and the middle terms, called the means.

hope it