Quibans 103: Over-subscribed

This Quibans is built around a news article from the Cambridge News headlined: “The top 10 hardest primary schools to enrol your children into in Cambridgeshire”.

Unusually, this Quibans starts with a discussion.  The article will appear later.

    School A has 30 places and 44 applications. 

    School B has 25 places and 38 applications. 

    Which school is harder to get a place at?

.

.

.

.

.

.

.

.

.

.

School A: 14 pupils were declined.

School B: 13 pupils were declined.

So School A is harder to get a place at.

But:

31.8% of applicants to School A were disappointed.

34.2% of applicants to School B were disappointed.

So School B is harder to get a place at.

 

We could also work out that for each place at School A there were 1.47 applications and for each place at School B there were 1.52 applications.  This means that School B had to disappoint a larger proportion of their applicants.

Which is the most appropriate version to use?

Here is the data from the article, with the schools listed in alphabetical order.  Rank them according to each method.

	Applications	Places
Fourfields Community Primary School	93	60
Godmanchester Bridge Academy	38	25
Middlefield Primary Academy	44	30
Park Lane Primary and Nursery School	75	60
Peckover Primary School	76	60
Ridgefield Primary School	50	30
Spinney Primary School	74	30
St Alban’s Primary School	58	30
Trumpington Park Primary	80	60
University of Cambridge Primary School	151	90

Which school is the hardest to get into?

 

Here is the article:

The top 10 hardest primary schools to enrol your children into in Cambridgeshire

The high number of applications these schools received to the places that were available, made them harder to gain a place.

20 NOV 2021

University of Cambridge Primary School, in Cambridge, had the highest number of first preference applications to the number of spaces it had available for children due to start in September 2021.

Top of Form

The hardest primary schools to gain a place in Cambridgeshire have been revealed.

Primary school preference data from Cambridgeshire County Council shows which schools were the most popular with parents and had more first place applications than spaces available.

In Cambridgeshire, the University of Cambridge Primary School is the hardest school to enrol a child at.

It received 151 first place preferences for children to start in September 2021, while the school only had an intake of 90 spaces available.

Top 10 primary schools that were the hardest to get children into in Cambridgeshire

1.    University of Cambridge Primary School, Cambridge
Rated outstanding by Ofsted, the school received 151 first preference applications, while it had 90 spaces available.

2.    Spinney Primary School, Cherry Hinton, Cambridge
Also rated outstanding by Ofsted, the school received 74 first preference applications, while it only had 30 places available.

3.    Fourfields Community Primary School, Yaxley
Rated good by Ofsted, the primary school received 93 first preference applications, while it had 60 places available.

4.    St Alban’s Primary School, Cambridge
Rated outstanding by Ofsted, this primary school received 58 first preference applications from parents, and had only 30 spaces available.

5.    Ridgefield Primary School, Cambridge
Rated good by Ofsted, it received 50 first preference applications, and had 30 places available.

6.    Trumpington Park Primary, Trumpington, Cambridge
This primary received 80 first preference applications, and could offer 60 places.

7.    Peckover Primary School, Wisbech
Rated good by Ofsted, this primary school received 76 first preference applications and had 60 spaces available.

8.    Park Lane Primary and Nursery School, Whittlesey
Rated good by Ofsted, the school received 75 first preference applications, and had 60 places available.

9.    Middlefield Primary Academy, St Neots
Rated outstanding by Ofsted, the primary school had 44 first preference applications, and had 30 spaces available.

10. Godmanchester Bridge Academy, Godmanchester
Rated good by Ofsted, this school received 38 first preference applications and had 25 places available.

 

Here is my table:

	Applications	Places	number declined	rank based on number	%age declined	%age accepted	Applicants per place	rank based on %age
University of Cambridge Primary School	151	90	61	1	40.4%	59.6%	1.68	3
Spinney Primary School	74	30	44	2	59.5%	40.5%	2.47	1
Fourfields Community Primary School	93	60	33	3	35.5%	64.5%	1.55	5
St Alban’s Primary School	58	30	28	4	48.3%	51.7%	1.93	2
Ridgefield Primary School	50	30	20	5	40.0%	60.0%	1.67	4
Trumpington Park Primary	80	60	20	6	25.0%	75.0%	1.33	8
Peckover Primary School	76	60	16	7	21.1%	78.9%	1.27	9
Park Lane Primary and Nursery School	75	60	15	8	20.0%	80.0%	1.25	10
Middlefield Primary Academy	44	30	14	9	31.8%	68.2%	1.47	7
Godmanchester Bridge Academy	38	25	13	10	34.2%	65.8%	1.52	6

 

My favourite column is “applicants per place”.  What will happen if you find the reciprocal of the numbers in that column?  (1 divided by each of the numbers)

If you decided to use the percentage ranking version, why might Park Lane not actually be number 10 in the county? 

.

.

.

(Because other schools that don’t appear in the article might, using the percentage version, be in the top 10.)

 

Source: https://www.cambridge-news.co.uk/news/top-10-hardest-primary-schools-22203950

 

Quibans 102: Fly me to the match

This story comes from the BBC Sport website.  It was then picked up by other news outlets.  Sky Sports included much of the same material, but the final bullet-point comes from their version of the story.

Man Utd defend decision to fly 100 miles to Leicester for Premier League game

United say they would not normally fly to the game but plans changed due to "circumstances". There were reports of traffic congestion on the M6.

Flying is a significant contributor to global warming and world leaders are meeting later this month in an attempt to avoid a climate catastrophe.

Aviation actually only contributes about 3.5% of the world's global carbon emissions, according to Carbon Brief, but only a very small percentage of the world flies frequently, meaning those who do are disproportionately responsible for these emissions.

Domestic flights are the least energy-efficient way to travel, as shown by the graphic below. France has moved to ban all short-haul domestic flights.

In response to BBC questions around the travel plans, United said they:

§  Have a policy to purchase certified green electricity for all club buildings and facilities.

§  Achieved the Carbon Trust Standard certification for a sixth consecutive year in 2020.

§  Achieved 12 consecutive years of energy and carbon reductions through the Manchester United Energy & Carbon Reduction Programme.

• Since the programme's launch in 2008, they have reduced annual carbon emissions by over 2,700 tonnes, a reduction equivalent to emissions produced by 540 homes for a year.

 

 

Questions:

1) In the table, what hasn’t been explained?

2) What is the link between the two figures in the table for cars?

3) Why might the figure for a bus be less than for a car, but more than for a coach?

4) Look at the final bullet point.  How many km driven by car are equivalent to the emissions produced by a home in a day?

Here are the figures used in the table (taken from a government document):

			Diesel
Activity	Type	Unit	kg CO2
Cars (by size)	Small car	km	0.14024
		miles	0.2257
	Medium car	km	0.16877
		miles	0.27161
	Large car	km	0.20763
		miles	0.33415
	Average car	km	0.17152
		miles	0.27603

 

Questions:

5) From the graphic in the story, a diesel car uses 171g per km.  Where is that figure?

6) What is the conversion factor between km and miles (it’s not exactly 1.6) ?

7) Find the average of the km figures for the small, medium and large cars.  Is this the same as the average car?  Comment!

Here is more data from the government document:

	kg CO2
Diesel	0.17152
Petrol	0.18014
Hybrid	0.11346
Battery Electric Vehicle	0.05973

Questions: 

8) Comment on the choice to use diesel cars in the graphic.

9) Do hybrid cars use their batteries exactly half the time?

10)  In the bus data (not yet shown), there is data about Local bus (not-London), Local London bus, Average local bus.  Do you expect the London or the not-London figure to be higher?  Will the average figure be halfway between the London and not-London figures, or closer to one of them (which one)? 

Here is the bus data:

Type	Unit	kg CO2
Local bus (not London)	passenger.km	0.11974
Local London bus	passenger.km	0.08163
Average local bus	passenger.km	0.10391
Coach	passenger.km	0.02728

Questions: 

11)  Were you right?

12) How many days of extra CO2 did each player use?

 

Answers:

1) These are presumably average figures.  Some cars will be more polluting than others because they have a bigger engine or are older, etc.  The same will be true for planes.  They haven’t explained why they used Diesel cars; I assume there are more petrol cars on the road.  They haven’t explained the +121g fully.  Does that give an equivalent total CO2 rating for a domestic flight of 254g per km?

2) A car with 1 passenger emits 171g per km.  Dividing this by 4 for a car with 4 people in it, which gives 42.75g per person – which has been rounded to 43g here.  Does this work?  A car with an additional 3 people in it will be heavier and will therefore presumably emit more…

3) I guess: a bus will emit a lot more than a car, but carries a lot more people, so the amount per person is less.  A coach stops less often than a bus (wasting fuel while idling), and is more likely to have a higher occupancy.

4) 2700 tonnes is the amount of CO2 produced by 540 homes in a year, so that is 5 tonnes = 5000kg per year.  This is 5000kg / 365 per day = 13.7kg = 13700g.  Dividing this by 171g, gives us 80km.  (I don’t know whether ‘produced by 540 homes’ includes the CO2 the occupants emit in their cars, or whether this is just the CO2 emitted by the building itself, for heating, cooking, food, etc.)

5) It looks like they have used the ‘average car’ figure (which seems fair enough).  This is   0.17152.  It should be rounded to 172g.

6) Dividing the miles figure by the km one gives 1.609 every time.  The next digit is either a 3 or a 4, so this is accurate to 4sf.

7) Working out the average of the small/medium/large, we get 0.172213.  The ‘average car’ value given is 0.17152, which is slightly different.  Presumably they didn’t work out this average but took into account that there are more medium cars on the road than small cars, etc.  The figures given for each size of car are already averages and it is sometimes problematic to take an average of averages.

8) Presumably there are more petrol cars on the road than any other type.  Did they choose diesel cars because it made cars look better (and therefore made flying look even worse)?  Or did they note that hybrids and electric cars and even better, so it would be fair to use diesel as a kind of average figure?

9) Using half petrol and half electric gives 0.11994, whereas the hybrid figure is 0.11346, so it doesn’t use battery for half the km.  (Using diesel and electric doesn’t work either.)

10)   I expect not-London to be higher, because rural buses will have fewer passengers on them than city buses and London is a big city.  There are many more not-London buses though, so I think the ‘average local bus’ figure will be closer to not-London and won’t be halfway between.

11)   Halfway between the not-London and London figures is 0.100685  The average is more than this, so it is closer to not-London.

12) We don't know whether they needed a coach at the other end to take them to their hotel, etc, but if we compare a 100-mile flight with a 100-mile coach journey, we get the following (and the distance by road is likely to be longer than 100-miles because on a plane you can go as the crow flies! And if the traffic was bad then the coach will have presumably used more fuel):  254g per km for the flight, subtract 27g per km for the coach gives an additional 227g per km.  Multiply this by 160km (equivalent to 100 miles) to get 36.32kg of CO2.  At 13.7kg per home per day, that's an extra 3 days worth of home-carbon to make that flight.  (And it's not just the players and subs but the rest of the support staff too).  

I wonder whether they will drive or fly home ... 

Sources:

https://www.bbc.co.uk/sport/football/58938198

https://www.skysports.com/football/news/12040/12435210/manchester-united-defend-decision-to-fly-to-leicester-for-premier-league-match

https://www.gov.uk/government/publications/greenhouse-gas-reporting-conversion-factors-2019