Math 9 · Unit 15: Interpreting and discussing results · Cambridge Lower Secondary Maths Stage 9

Questions

1. 1. The table shows the time it takes for 45 students to complete a puzzle. The midpoint is the number halfway between the lower and upper values of the class (halfway between 0 and 10 is 5). Copy and complete the table: put each missing midpoint in its box.

   Fill the blanks with these.

   • 45
   • 40
   • 50
   • 55
   • 60
   • 35
   Check

2. 2. The table shows the time it takes for 45 students to complete a puzzle. Where is the third point of the frequency polygon plotted?

   • at 30 and frequency 8
   • at 25 and frequency 15
   • at midpoint 25 and frequency 8
   • at 20 and frequency 6
   Check

3. 3. The table shows the heights of twenty apple trees. What are the midpoints of the four classes?

   • 270, 290, 310, 330
   • 260, 280, 300, 320
   • 280, 300, 320, 340
   • 3, 7, 9, 1
   Check

4. 4. The table shows the times taken by the students in class 9C to complete a cross-country run. How many students are there in class 9C?

   • 4
   • 32
   • 27
   • 20
   Check

5. 5. The table shows the times taken by the students in class 9C to complete a cross-country run. Copy and complete the table: put each missing midpoint in its box.

   Fill the blanks with these.

   • 17
   • 16
   • 13
   • 14
   • 15
   • 12
   • 11
   Check

6. 6. The table shows the times taken by the students in class 9C to complete a cross-country run. What fraction of the students took less than 14 minutes to complete the run?

   • 3/8
   • 5/8
   • 1/2
   • 5/12
   Check

7. 7. The table shows the times taken by the students in class 9C to complete a cross-country run. Zara says: "The frequency polygon shows that the fastest student took 11 minutes to complete the run." Is Zara correct?

   • Yes
   • No
   Check

8. 8. Twenty people recorded the time, in seconds, it took them to throw a double six with two dice. Here are the results: 21, 6, 40, 29, 32, 15, 25, 37, 28, 15, 12, 30, 18, 35, 22, 45, 30, 9, 17, 23. Complete the frequency column: put each frequency in its box.

   Fill the blanks with these.

   • 5
   • 7
   • 3
   • 6
   • 2
   • 4
   • 8
   • 1
   Check

9. 9. Times (s) to throw a double six: 21, 6, 40, 29, 32, 15, 25, 37, 28, 15, 12, 30, 18, 35, 22, 45, 30, 9, 17, 23. How many are in 20 < t ≤ 30?

   • 6
   • 7
   • 9
   • 8
   Check

10. 10. Mia completed a survey on the heights of people going on a roller-coaster ride at a theme park on two days. The tables show the results of her survey. How many people were surveyed on each day?

    • Wednesday 22, Saturday 25
    • Wednesday 50, Saturday 50
    • Wednesday 40, Saturday 41
    • Wednesday 50, Saturday 25
    Check

11. 11. Mia completed a survey on the heights of people going on a roller-coaster ride at a theme park on two days. The tables show the results of her survey. What are the midpoints of the four classes, the same on both days?

    • 4, 6, 22, 18
    • 120, 140, 160, 180
    • 130, 150, 170, 190
    • 140, 160, 180, 200
    Check

12. 12. Mia completed a survey on the heights of people going on a roller-coaster ride at a theme park on two days. The tables show the results of her survey. Compare the two frequency polygons. What can you say about the heights of the people on the two days?

    • On Wednesday most riders were taller; on Saturday most were shorter.
    • On both days most riders were between 160 and 180 cm.
    • The riders were about the same height on both days.
    • On Wednesday most riders were shorter; on Saturday most were taller.
    Check

13. 13. Harsha completed a survey on the number of hours that the athletes from two different clubs spend training each week. The frequency diagrams show the results of her survey. Compare the two frequency polygons. What can you say about the number of hours the athletes from the two clubs train?

    • Most athletes at both clubs train for 5 to 10 hours.
    • The Harriers train for more hours; most Falcons train 5 to 15 hours, most Harriers 15 to 25.
    • Both clubs train for about the same number of hours.
    • The Falcons train for more hours than the Harriers.
    Check

14. 14. Harsha completed a survey on the number of hours that the athletes from two different clubs spend training each week. The frequency diagrams show the results of her survey. How many athletes from each club were surveyed?

    • Falcons 58, Harriers 70
    • Falcons 70, Harriers 68
    • Falcons 68, Harriers 70
    • Falcons 24, Harriers 26
    Check

15. 15. Harsha completed a survey on the number of hours that the athletes from two different clubs spend training each week. The frequency diagrams show the results of her survey. Do you think it is fair to make a comparison using these sets of data?

    • Yes
    • No
    Check

16. 16. How do you finish a frequency polygon?

    • Draw bars for each class.
    • Draw a line of best fit.
    • Join the points with straight lines.
    • Join the points with a smooth curve.
    Check

17. 17. The table shows the mass of 50 girls when they are 6 months old. Lucia regroups the data into fewer groups. Copy and complete Lucia's frequency table: put each frequency in its box.

    Fill the blanks with these.

    • 12
    • 23
    • 9
    • 26
    • 14
    • 13
    Check

18. 18. The table shows the mass of 50 girls when they are 6 months old, and Lucia's regrouped table. Compare the frequency polygons for the 6-class table and for Lucia's 3-class table. Which gives better information on the mass of girls who are 6 months old?

    • Lucia's, because its frequencies are bigger
    • the 6-class one, because it shows more detail
    • Lucia's, because it has fewer points
    • They give exactly the same information.
    Check

19. 19. Sienna wants to have more groups in her frequency table. Here is the start of the table she draws, with classes 0.05 kg wide, from the masses in the first table. How many groups will there be in Sienna's table, and can she complete it using the frequencies in the first table?

    • 12 groups, and yes
    • 6 groups, and yes
    • 12 groups, and no
    • 6 groups, and no
    Check

20. 20. The time, in seconds, it took 60 students to solve a maths problem was recorded. Here are the results: 20, 44, 34, 50, 33, 41, 38, 43, 53, 35, 47, 40, 27, 49, 24, 35, 39, 21, 38, 36, 23, 32, 30, 40, 35, 25, 32, 47, 33, 48, 45, 30, 41, 33, 49, 37, 54, 47, 34, 45, 36, 56, 35, 58, 40, 20, 51, 31, 26, 39, 30, 41, 35, 54, 37, 46, 22, 42, 31, 29. The quickest time is 20 and the slowest 58. Group the times as 20 ≤ t < 30, 30 ≤ t < 40, 40 ≤ t < 50 and 50 ≤ t < 60. What are the frequencies?

    • 10, 25, 17 and 8
    • 11, 25, 16 and 6
    • 10, 25, 18 and 7
    • 12, 24, 18 and 6
    Check