Organizing Data
This type of graph is best for displaying the distribution of quantitative data using adjacent bars.
Adjacent means very near, or touching.
What is a histogram?
This measure of center is found by adding all the data values and dividing by the number of values.
What is the mean?
A student is at the 75th percentile on an exam. This means the student scored better than approximately what percent of the class?
What is 75%.
This manipulation of an axis may cause small differences to appear much larger than they actually are.
What is "not starting the y-axis at 0"?
Every student at the university has an equal chance of being selected. What type of sampling is this?
What is "a simple random sample"?
This display organizes numerical data by separating each value where the beginning digit(s) is written on the left and the ending digit is written on the right.
What is a stem-and-leaf plot?
This measure of center is the middle value when the data are arranged from least to greatest.
What is the median?
A student is at the 75th percentile on an exam. There were 30 students in the class. This means the student scored better than approximately how many students?
What is 22 students?
This technique is misleading because it leads to different sized groups (which could lead to a distorted display of the data).
What is "using unequal bin widths"?
A researcher surveys every 20th student who walks into the student center. What type of sampling is this?
What is "systematic sampling"?
Suppose 8 out of 40 students own a pet cat. What percent of students own a cat?
A data set is changed by increasing every value by 10.
As a result, this measure of spread will stay exactly the same.
What is the standard deviation.
This percentile will always be equal to the median.
What is the 50th percentile.
A newspaper reports that ice cream sales and shark attacks both increase during summer. The study concludes the town should stop ice cream sales so shark attacks will go down. This type of mistake is being made.
What is "confusing correlation with causation"?
A college separates students into freshmen, sophomores, juniors, and seniors, then randomly selects students from each group.
What is a "stratified sample"?
When a graph has bars that touch each other, this tells you the data is most likely what type of data?
What is quantitative data?
A data set has a standard deviation of 0. What must be true about the data?
What is "All the data values must be the same"?
Two students scored at the 30th and the 80th percentile. Which student performed better relative to the rest of the class?
Who is the student at the 80th percentile?
This technique is misleading because it emphasizes something about the bars that doesn't matter.
What is "using different width of bars"?
What is "cluster sampling"?
You collected data on students' favorite pizza toppings. Which graph would be more appropriate?
(Two acceptable answers)
What is a bar chart or a pie chart.
Two classes have the same mean exam score. Class A has a standard deviation of 3, while Class B has a standard deviation of 12.
You can you tell me this fact about the exam scores for these classes.
What is "The grades in Class B are more spread out"?
A student is at the 95th percentile on a test. They mistakenly think that means they scored a 95% on the test.
What is a sentence you can tell them to correct their thinking?
What is "It means they scored higher than 95% of all the other students".
A survey asks "Don't you agree that our campus needs more parking?" before asking students their opinion.
What is wrong with the question?
(Hint: It is a L_______ing question.)
What is "a leading question".
These types of sampling methods both start by separating the population into several different groups.
What are "cluster" and "stratified" sampling methods?