Averages (including IQR): WJEC GCSE Numeracy Intermediate June 2022 Unit 2 Q5

Numeracy Intermediate June 2022 Unit 2 Q5

WJECIntermediateCurrent spec5 marksAverages (including IQR)Time-Series

5. An engine normally runs at 100°C.
When the engine runs at 110°C or more, a warning light comes on.

A section of the temperature chart for the engine, from 12:00 to 16:00, is shown below.

Temperature of the engine (°C), from 95 to 115, against time from 12:00 to 16:00, with points plotted every 15 minutes: 100, 102, 103, 104, 105, 104, 105, 107, 110, 110.5, 110, 110, 109, 111, 111, 110, 109

(a)

How often was the temperature of the engine recorded?
Circle your answer. [1]

Every 5 minutes Every 12 minutes Every 15 minutes

Every \(2\frac{1}{2}\) minutes Every 30 minutes

(b)

At what time was it first recorded that the warning light had come on? [1]

(c)

What was the range of the recorded temperatures of the engine between 12:00 and 16:00? [1]

(d)

(i)

Use the graph paper below to plot the recorded temperature of the engine at 12:00, 13:00, 14:00, 15:00 and 16:00 only. [1]

Blank graph paper: temperature of the engine (°C) from 60 to 120 on the vertical axis, time from 12:00 to 16:00 on the horizontal axis

(ii)

Why is the graph you have drawn misleading? [1]

Scheme	Marks	Comments
Every 15 minutes	B1

Scheme	Marks	Comments
14(:)00 or 2 p.m.	B1	Allow an answer of 2 or 14(:)00p.m. Do not accept an answer of 2 a.m.

Scheme	Marks	Comments
11 (°C)	B1

Mark scheme (d)

Scheme	Marks	Comments
(i) 5 points plotted accurately: (12:00, 100), (13:00, 105), (14:00, 110), (15:00, 109), (16:00, 109)	B1	Plotting of 100 and 110 should be intention of being on the appropriate line Tolerance for plotting 105 and 109 is within the appropriate small square Ignore any joining of plotted points
(ii) Appropriate reason, e.g. ‘the rise in temperature doesn’t look very much’, ‘it is only temperatures from 100°C that are needed’, ‘not showing the warning light was on as often as it was’, ‘it doesn’t show the fluctuating temperature’, ‘doesn’t show the number of warnings given (when over 110°C)’, ‘more details are required to show the warnings’,	E1	Ignore additional spurious or incorrect statements for accepted and allowed responses Allow, e.g. ‘misleading’ with a suitable reason given ‘doesn’t give the same detail (as the first graph)’, ‘doesn’t give the details of temperature changes’, ‘it doesn’t show all the temperature changes’, ‘doesn’t give the same accuracy (as the first graph)’, ‘doesn’t give the accurate temperature changes’, ‘only shows specific times’, ‘only recording once an hour’, ‘there is no data to fill the gaps’, ‘the temperatures between are not shown’, It doesn’t give all the information’, ‘not all the points plotted from the previous graph’, ‘small scale’, ‘the temperature goes up in 2’s rather than 0.5’, ‘lost loads of the data’, ‘there are not many points’, ‘it doesn’t change much to show when something went wrong’, ‘there are no temperatures recorded below 100°C’ Do not accept, e.g. ‘misleading’, ‘not accurate’, ‘it doesn’t give the accurate temperatures’, ‘the temperatures aren’t the same as the first graph’, ‘most points are not over 110°C’, ‘the temperature goes higher on the axis than the other graph’