Center describes where the 'middle' of data lies; spread describes how far data extends from that center.
Two pizza delivery services both average 30-minute delivery (same center). But Service A ranges 28-32 minutes, while Service B ranges 10-50 minutes. Same center, wildly different spread. You'd trust A for consistent timing.
Showing a random 20 of 50 problems.
Example 1
easy
True or false: two data sets with equal means must look identical.
Example 2
medium
A restaurant's lunch wait times (minutes) — Week 1: 5, 6, 5, 7, 5. Week 2: 3, 10, 4, 8, 3. Find the mean and range for each week and explain which week had more predictable service.
Example 3
medium
Two basketball players average 20 points/game. Player A scores between 18 and 22; Player B scores between 0 and 40. Which is more reliable?Points per game: both average 20 pts/game
Example 4
easy
Set A: 29,30,31. Set B: 10,30,50. Same center?Set A: {29, 30, 31} vs Set B: {10, 30, 50}
Example 5
easy
Set A: 29,30,31. Set B: 10,30,50. Which has more spread?
Example 6
medium
A weather report says 'average high this week is 75 degrees.' What is missing?
Example 7
easy
Which describes 'how scattered': center or spread?
Example 8
easy
Bus A arrives in 15±1 min; Bus B arrives in 15±12 min. Which is more predictable?
Example 9
easy
Quiz scores: Class A all 80; Class B has scores from 60 to 100. Which has zero spread?
Example 10
easy
Which question does 'center' answer: 'where is the middle' or 'how scattered'?
Example 11
medium
If you multiply every value by 2, what happens to the center and the spread?
Example 12
easy
Two delivery services average 30 min; A ranges 28-32, B ranges 10-50. Which is more reliable?Delivery time (minutes): both average 30 min
Example 13
hard
Pizza shop A delivers in 25±3 min; shop B delivers in 30±1 min. You need food in 32 minutes. Which is the safer bet?
Example 14
easy
Set A: 99,100,101. Set B: 50,100,150. Which has more spread?
Example 15
medium
Two stocks both gain 5% a year on average. Stock A swings ±1%; Stock B swings ±30%. Which is riskier?
Example 16
medium
A team's daily commutes (min): 30,31,30,29,30. Median commute is 30. What does the small spread imply?
Example 17
medium
Set A: {50,50,50}, Set B: {0,50,100}. Compare center and spread.Set A: {50, 50, 50} vs Set B: {0, 50, 100}
Example 18
hard
True or false: it is possible for one data set to have a larger mean but a smaller spread than another. Give an example.
Example 19
medium
Data has center 50 and large spread. Adding 10 to every value, what changes?
Example 20
medium
Two dartboards: thrower A's darts land {9,10,11}, thrower B's land {0,10,20}. Both 'aim' is the bullseye (center 10). Compare.Dart landing distance from bullseye (cm): center = 10 for both