Realizing that your survey approach would not produce a random and representative sample, you gather some friends to help sample. You place one surveyor outside each building. You each randomly select 20 students leaving the buildings that morning and tally the results: 5 people decline to participate, 35 tell you that their class was full, and 20 tell you that their class was not full. Is your sample now representative of all classes that morning?

Ascientist wants to use a model to present the results of his detailed scientific investigation. why would a model be useful? a )because the model makes the concepts easier to understand b) because the model is easy to put together and to use c) because the model prevents other scientists from asking questions d) because the model requires the audience to pay full attention to it i don't know what to choose because between a and d a is much more likely than d because it only wants to get the attention of the audience. i'm confuse.