ATAR Notes: Forum
VCE Stuff => VCE Mathematics => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE General & Further Mathematics => Topic started by: almostdonewithschooling on February 17, 2019, 10:13:45 am
-
Hey guys, I need some clarification.
For question 6, the ans A, but I said it was B because, when I drew it into my cas, it showed me negatively skewed. On the other hand, median is larger so it’s pos skewed. Doesn’t make sense. My question is, why is it neg skewed on the cas??? (I double checked every num)
For question 7, the mean is 155.67, median is 159 and mod height is 163.
I got the first bit of it (lower), but I don’t get how the modal height is lower than the med height. (163 isn’t lower than 159)
That’s all. Thank you so much
-
Q6.
Not entirely sure what's going on with your CAS. Maybe the axes were accidentally flipped or something else happened. Sorry, my mistake. The question shows a negatively-skewed distribution and your CAS is right. The answer was probably changed a bit. (See my next post in this thread for clarification as to why.) In future, you can also double check the answer by flipping the page on its side so that the line that divides the stem and leaf for the boys is horizontal. Reorganise the plot so it's in ascending order (in this case, the plot should be a mirror image). This gives a positively skewed graph.
Note: This is merely a method that works to eyeball stem and leaf plots though, so it's not an official method and can only be used to double check this specific type of question. If this checking method doesn't make sense, I might draw an image of what I mean; just say the word.
Q7. I think you're right and the person probably changed the question, forgetting to change the answer.
P.S. Please post questions in the VCE Further Questions Thread next time. Thanks.
EDIT: Shown in strikethrough and bold above.
-
It didn’t work. This is what it gave me
-
It didn’t work. This is what it gave me
I re-checked the question just now. You (and your CAS) are right, it is negatively skewed; just realised I messed up and will edit the above post. Sorry for the confusion and my mistake. Median is larger than the mean and is a characteristic of negatively-skewed data due to the majority of the data shifting more to the right (tail points left). There's a diagram to show what I mean here. The eyeball method is correct though, so that part's fine.