Question 1
These are Rahul's 10 test scores.
9
8
9
10
7
x
9
9
x
7
The mean of these scores is 8.
Find the interquartile range.
You must show all your working.
These are Rahul's 10 test scores.
9
8
9
10
7
x
9
9
x
7
The mean of these scores is 8.
Find the interquartile range.
You must show all your working.
1068+2x=8 or better
x=6
Lower quartile = 6.5 or 6.75 or 7, or upper quartile = 9
2 or 2.25 or 2.5 nfww
Jean asks 600 people to choose their favourite sport. The pie chart shows some of this information.
Show that 100 people choose tennis.
36060×600 oe
Work out how many people choose rugby.
45
M1 for 36027×600 oe
125 people choose cricket and the rest choose swimming.
Complete the pie chart to show this information.
Correct straight line on the pie chart
B1 for 75
The heights of some plants are measured:
- smallest height =0.6 cm
- range =8.1 cm
- median =5.2 cm
- lower quartile =3.4 cm
- interquartile range =4.1 cm.
On the grid, draw a box-and-whisker plot to show this information.
Correct diagram
0.63.45.27.58.7
B1 for any three of 0.6, 3.4, 5.2, 7.5, 8.7 correctly placed
B1 for 7.5 and 8.7 seen
50 students answer a mathematics question.
The table shows the time, t seconds, taken by each student to answer the question.
\begin{tabular}{|l||c|c|c|c|c|}
\hline Time (t seconds) & 10<t⩽20 & 20<t⩽25 & 25<t⩽30 & 30<t⩽50 & 50<t⩽80 \\
\hline Frequency & 2 & 8 & 12 & 16 & 12 \\
\hline
\end{tabular}
Calculate an estimate of the mean.
39.2
M1 for mid-values soi
M1 for Σfx with x in correct interval including boundaries
M1 dep for 50Σfx dep on second M1
A student measures the height, h cm, of each of 400 plants.
The cumulative frequency diagram shows the results.
Use the diagram to find an estimate for
the median cm [1]
30
1
the interquartile range cm [2]
20
B1 for upper quartile =37 or lower quartile =17.
the 80th percentile cm [2]
39
2
B1 for 320 seen
the number of plants with a height greater than 60 cm .
34 to 38
2
B1 for 362 to 366 seen
The heights are also shown in the frequency table.
Complete the histogram to show this information.
Correct histogram, correct widths and heights 8 cm,12.4 cm,1.9 cm.
B1 for each column.
If 0 scored, SC1 for frequency densities 8, 12.4, 1.9 seen.
Students in class P take a test.
These statistics show information about their marks.
- lower quartile =38
- median =53
- interquartile range =28
- range =81
- highest mark =96
Draw a box-and-whisker plot to represent this information.
Correct box-and-whisker plot. B3
Lowest =15, LQ =38, Median =53, UQ =66, Highest =96.
B1 for UQ =66 or Lowest =15 seen or implied.
M1 for at least three values correct within the box-and-whisker plot.
Students in class Q take the same test.
For class Q, the median is 49 and the interquartile range is 35.
Make two comments comparing the distribution of marks for class P with that of class Q.
1.
2.
Class Q scored fewer marks on average [as median is lower] oe.
Class Q have a larger spread of marks [as IQR is higher] oe.
B1 for each valid comparison.