Practice Data (Abstract) in Math
Use these practice problems to test your method after reviewing the concept explanation and worked examples.
Quick Recap
Data is a collection of recorded observations or measurements used to describe, analyze, or make inferences about a phenomenon or population.
Data is raw material for understanding—numbers, words, or categories we collect to answer questions.
Showing a random 20 of 50 problems.
Example 1
mediumA spreadsheet lists temperatures but some cells are blank. What should an analyst do before computing the mean?
Example 2
mediumTwo datasets answer 'How tall are students?': one lists exact heights, the other lists 'short/medium/tall'. Which supports computing a mean height?
Example 3
mediumPopulation vs sample: a researcher measures all 30 students in one class to learn about the class. Is this a population or a sample?
Example 4
mediumA dataset has 30% of 'income' entries blank. Should you report the mean income?
Example 5
mediumA survey asks: (1) What is your ZIP code? (2) How many hours do you sleep per night? (3) Rate your satisfaction 1–5. Classify each and identify potential misclassification pitfalls.
Example 6
challengeA dataset combines heights measured in inches (US branch) and centimeters (EU branch) in one column without labels. Why is this dataset unusable as-is, and what fixes it?
Example 7
mediumA researcher records survey responses only from people who answered an online ad. What sampling problem is this?
Example 8
mediumA researcher wants to study average commute time. They survey only people leaving a train station at 8 a.m. Name the data problem and its effect.
Example 9
easyYes/no answers to 'Do you own a pet?' are collected. What type of data is this?
Example 10
easyWhat is the difference between an observation and a variable?
Example 11
mediumA study finds higher cell-phone use correlates with lower test scores in 7th graders. Does the data show that phones cause lower scores?
Example 12
mediumA column lists ice cream sales (numeric) per day. Another lists 'season' (winter/spring/summer/fall). Which can you compute an average of?
Example 13
mediumSort these into numerical or categorical: (a) ZIP code, (b) number of pets, (c) brand of phone, (d) heart rate (bpm).
Example 14
easyA survey asks 'Are you a vegetarian?' and records yes/no. What type of data is this?
Example 15
easyA class records each student's favorite fruit (apple, banana, orange). Is this numerical or categorical data?
Example 16
mediumA dataset of customer reviews contains both star ratings (1-5) and written comments. Which part is numerical and which is text/categorical?
Example 17
easyIn a data table, each row usually represents one ___.
Example 18
easyZip codes are stored as numbers like 90210. Should they be treated as numerical data for averaging?
Example 19
mediumA class collects everyone's height in inches but writes some as feet+inches. Why is the dataset hard to analyze before cleaning?
Example 20
easyA pollster surveys 20 students out of 600. The 20 are a ___ and the 600 are the ___ .