Data Analysis Flashcards

A two-way table shows that 15 boys and 20 girls prefer science, while 10 boys and 5 girls prefer art. How many total students prefer science?

Answer: 35

Total science = 15 boys + 20 girls = 35 students.

A data set has a mean of 30 and a median of 25. What does this suggest about the distribution?

Answer: The data is skewed right

When the mean is greater than the median, the distribution is skewed right (pulled up by high values).

A student wants to find out which lunch option is most popular among 300 students. She surveys every 10th student in line. What type of sampling is this?

Answer: Systematic sampling

Selecting every nth person from a list or sequence is called systematic sampling.

The dot plot shows values: 3, 3, 4, 5, 5, 5, 6, 7. If the value 7 is removed, how does the mean change?

Answer: It decreases

Removing a high value (7) lowers the sum and thus decreases the mean.

Which statement best describes a negative correlation on a scatter plot?

Answer: As x increases, y decreases

A negative correlation means that as one variable increases, the other decreases, showing a downward trend.

A bar graph shows monthly rainfall. April had 4 inches, May had 6 inches, and June had 3 inches. What was the total rainfall for these three months?

Answer: 13 inches

4 + 6 + 3 = 13 inches of total rainfall.

A student claims that because ice cream sales and drowning rates both rise in summer, eating ice cream causes drowning. What error is the student making?

Answer: Confusing correlation with causation

Two variables rising together shows correlation, but does not mean one causes the other — both are influenced by a third factor (hot weather).