Example Question #1 : Statistics And Probability
The scatter plot provided displays a group of students' test scores versus the number of missing assignments the students have. Based on plot, select the best answer that describes the direction of the points.
A negative, non linear association
A negative, linear association
A positive, linear association
A positive, nonlinear association
A negative, linear association
The data points in the scatter plot move up the y-axis as the x-axis decreases; thus the data points show a negative association. Also, the data points do not curve, or go up and down, but gradually decreased; thus the scatter plot shows a linear association. We could even draw a "best fit" line:
Example Question #2 : Statistics And Probability
A middle school teacher conducted a survey of the grade class and found that students were athletes and of those students drink soda. There were students that were not athletes, but drank soda. Last, they found that students did not have a curfew nor were on honor roll. Given this information, how many students don't drink soda?
To help answer this question, we can construct a two-way table and fill in our known quantities from the question.
The columns of the table will represent the students who are athletes or are not athletes and the rows will contain the students who drink soda or do not drink soda. The first bit of information that we were given from the question was that students were athletes; therefore, needs to go in the "athlete" column as the row total. Next, we were told that of those students, drinks soda; therefore, we need to put in the "athlete" column and in the "drinks soda" row. Then, we were told that students were not athletes, but drink soda, so we need to put in the "not an athlete" column and the "drinks soda" row. Finally, we were told that students are not athletes or soda drinkers, so needs to go in the "not an athlete" column and "doesn't drink soda" row. If done correctly, you should create a table similar to the following:
Our question asked how many students don't drink soda. We add up the numbers in the "doesn't drink soda" row to get the total, but first we need to fill in a gap in our table, students who were athletes, but don't drink soda. We can take the total number of students who are athletes, , and subtract the number of students who drink soda,
This means that students who are athletes, don't drink soda.
Now, we add up the numbers in the "doesn't drink soda" row to get the total:
This means that students don't drink soda.
Example Question #3 : Statistics And Probability
Select the answer choice with a data set that includes an outlier.
To answer this question correctly, we need to recall what "outlier" means. An outlier is a value that is much smaller or larger than the rest of the values in a set of data. Also, a data point that does not follow the same pattern as the rest of the set could be described as an outlier.
In this case, we are looking for a number that doesn't match with the other numbers provided in a set:
has a much larger value than the other number in the set; thus, is an outlier.