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📊 Statistics is the grammar of science. Every number tells a story!

Practice: Statistics

Basic to Moderate

Basic to Moderate (1-20)

â–¶1. The ages of 5 children are: 6, 8, 10, 12, and 14. What is the mean (average) age? Explain every step.
Answer: 10 years
Explanation:
  • First, add up all the ages: 6 + 8 + 10 + 12 + 14 = 50
  • There are 5 children.
  • Now, divide the total by the number of children: 50 ÷ 5 = 10
  • So, the mean age is 10 years. Imagine sharing 50 candies equally among 5 kids—each gets 10!
â–¶2. The numbers are: 3, 7, 9, 12, 15, 18, 21. What is the median? Show how you find it.
Answer: 12
Explanation:
  • First, put the numbers in order (they already are!).
  • There are 7 numbers, so the middle one is the 4th: 12
  • The median is the number in the middle when you line them up from smallest to biggest.
â–¶3. The numbers are: 2, 4, 4, 6, 8, 8, 8, 10. What is the mode? Why?
Answer: 8
Explanation:
  • The mode is the number that appears most often.
  • 2 appears once, 4 appears twice, 6 once, 8 three times, 10 once.
  • So, 8 is the mode because it shows up the most (3 times).
â–¶4. The numbers are: 5, 12, 7, 20, 15. What is the range? Explain what range means.
Answer: 15
Explanation:
  • Range = Biggest number - Smallest number
  • Biggest is 20, smallest is 5. So, 20 - 5 = 15
  • The range tells us how spread out the numbers are, like the tallest and shortest in a group!
â–¶5. The test scores of 6 students are: 80, 85, 90, 95, 100, 100. What is the mode and what does it mean?
Answer: 100
Explanation:
  • The mode is the number that appears most often.
  • 100 appears twice, all others appear once.
  • So, the mode is 100. This means 100 is the most common score in this group.
â–¶6. The numbers are: 2, 4, 6, 8, 10, 12. What is the mean and the range?
Answer: Mean = 7, Range = 10
Explanation:
  • Add up: 2 + 4 + 6 + 8 + 10 + 12 = 42
  • There are 6 numbers. Mean = 42 ÷ 6 = 7
  • Range = 12 - 2 = 10
  • So, the mean is 7 and the range is 10.
â–¶7. The heights (in cm) of 8 children are: 120, 125, 130, 135, 140, 145, 150, 155. What is the median height?
Answer: 137.5 cm
Explanation:
  • There are 8 numbers, so the median is the average of the 4th and 5th: (135 + 140) ÷ 2 = 137.5
  • The median is the "middle" value when the numbers are in order.
â–¶8. The numbers are: 5, 7, 7, 8, 10, 12, 12, 12, 15. What is the mode and the range?
Answer: Mode = 12, Range = 10
Explanation:
  • 12 appears 3 times, more than any other number, so mode = 12.
  • Range = 15 - 5 = 10
â–¶9. The numbers are: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10. What is the mean, median, and range?
Answer: Mean = 5.5, Median = 5.5, Range = 9
Explanation:
  • Mean: Add up all numbers (1+2+...+10 = 55), divide by 10: 55 ÷ 10 = 5.5
  • Median: 10 numbers, so average of 5th and 6th: (5+6)/2 = 5.5
  • Range: 10 - 1 = 9
â–¶10. The scores in a game are: 8, 10, 12, 14, 16, 18, 20. What is the mean and the mode?
Answer: Mean = 14, Mode = None
Explanation:
  • Add up: 8+10+12+14+16+18+20 = 98, divide by 7: 98 ÷ 7 = 14
  • Mode: All numbers appear once, so there is no mode.
â–¶11. A bar graph shows the number of apples sold each day: Mon-10, Tue-15, Wed-20, Thu-25, Fri-30. On which day were the most apples sold? What is the range?
Answer: Friday, Range = 20
Explanation:
  • Most apples sold on Friday (30 apples).
  • Range = 30 (Friday) - 10 (Monday) = 20
  • Bar graphs help us see which day is the highest and lowest easily!
â–¶12. A pie chart shows: Red-25%, Blue-35%, Green-40%. If there are 200 marbles, how many are green?
Answer: 80 marbles
Explanation:
  • Green is 40% of 200 marbles.
  • 40% means 40 out of every 100, so 200 × 0.40 = 80
  • So, there are 80 green marbles.
â–¶13. In a survey, 12 kids like pizza, 8 like burgers, and 5 like pasta. What is the mode of their favorite food?
Answer: Pizza
Explanation:
  • Pizza is chosen by the most kids (12), so it is the mode.
  • Mode can be used for things other than numbers, like favorite foods!
â–¶14. The numbers are: 2, 4, 6, 8, 10, 12, 14. What is the median and the range?
Answer: Median = 8, Range = 12
Explanation:
  • Median: 7 numbers, so the 4th is the median: 8
  • Range: 14 - 2 = 12
â–¶15. A dice is rolled 60 times. It lands on 6 a total of 15 times. What is the experimental probability of getting a 6?
Answer: 1/4 or 0.25
Explanation:
  • Probability = Number of times 6 comes up ÷ Total rolls = 15 ÷ 60 = 0.25
  • So, the chance of getting a 6 is 1 out of 4, or 25%.
â–¶16. The test scores are: 70, 80, 90, 100, 100, 100, 90, 80, 70. What is the mode and the mean?
Answer: Mode = 100, Mean = 86.67
Explanation:
  • Mode: 100 appears 3 times, more than any other score.
  • Mean: Add up all scores: 70+80+90+100+100+100+90+80+70 = 780. There are 9 scores. Mean = 780 ÷ 9 ≈ 86.67
â–¶17. A class has 10 boys and 15 girls. What fraction of the class are girls? What percent?
Answer: Fraction = 15/25 = 3/5, Percent = 60%
Explanation:
  • Total students = 10 + 15 = 25
  • Fraction = 15/25 = 3/5
  • Percent = (15 ÷ 25) × 100 = 60%
â–¶18. The numbers are: 4, 8, 12, 16, 20, 24. What is the mean, median, and range?
Answer: Mean = 14, Median = 14, Range = 20
Explanation:
  • Mean: Add up all numbers: 4+8+12+16+20+24 = 84, divide by 6: 84 ÷ 6 = 14
  • Median: 6 numbers, so average of 3rd and 4th: (12+16)/2 = 14
  • Range: 24 - 4 = 20
â–¶19. A bar graph shows the number of books read by students: Anna-5, Ben-8, Cara-6, Dan-7. Who read the most? What is the range?
Answer: Ben, Range = 3
Explanation:
  • Ben read the most books (8).
  • Range = 8 (Ben) - 5 (Anna) = 3
â–¶20. A pie chart shows: Apples-30%, Bananas-20%, Cherries-50%. If there are 120 fruits, how many are cherries?
Answer: 60
Explanation:
  • Cherries are 50% of 120 fruits.
  • 50% means half, so 120 × 0.5 = 60
  • So, there are 60 cherries.