IBDP Computer Science B2.1 Programming fundamentals HL Paper 2 - New Syllabus

(a)
For the correct answer, suitable variables include:

• TemperatureReading
• DailyMaximumTemperature
• TotalTemperature

Only one suitable answer is required.

Explanation: The variables must provide the temperature readings and the value calculated from those readings. The mean can then be calculated from the total temperature and the number of readings.

(b)
For the correct answer:

1. Identify/select the data for the mean daily maximum temperatures and the corresponding years.
2. Select the appropriate line graph chart type.
3. Add the correct chart heading and label the axes as Temperature (°C) and Year.

Explanation: The years form the horizontal axis and the mean daily maximum temperatures form the vertical axis. A line graph is appropriate because the data represents a measurement changing over time.

(c)
For the correct answer, any two suitable reasons:

• The data is displayed visually, making trends easier to identify.
• The graph shows the increase in mean daily temperatures over time more clearly.
• Data can be compared with similar graphs for different regions or time periods.
• Complicated data is easier to understand when presented visually.

Explanation: A graphical representation allows patterns and trends to be identified more quickly than examining a large collection of numerical values.

(d)
For the correct answer:

• Collecting data once per hour gives 24 recordings per day, compared with 1440 recordings if data were collected once per minute.
• This reduces the amount of processing and storage required, while the small changes occurring between individual minutes may not significantly affect the study.

Explanation: Collecting more frequently produces much more data. If minute-by-minute changes are not important to the investigation, hourly measurements provide sufficient information while reducing storage and processing requirements.

(e)
For the correct answer:

• Create two parallel 1D arrays, such as TIME and TEMP, each with a size of 24.
• Initialize the TIME array with the 24 hourly times from 00:00 through 23:00.
• Use a loop counter, such as N.
• Repeat the process 24 times.
• For each position, identify or display TIME(N) and store the corresponding temperature in TEMP(N).

Example structure:

TIME[0] = 00:00
TIME[1] = 01:00
TIME[2] = 02:00
...
TIME[23] = 23:00

TEMP[0] = temperature at 00:00
TEMP[1] = temperature at 01:00
TEMP[2] = temperature at 02:00
...
TEMP[23] = temperature at 23:00

Explanation: The arrays are parallel because the same index identifies related values. For example, TIME[5] identifies the time and TEMP[5] stores the temperature recorded at that time.

(f)
For the correct answer:

• Initialize variables for the total temperature and total night-time temperature.
• Initialize MIN and MAX appropriately.
• Use a loop that iterates through all 24 readings.
• Add every temperature to the total temperature.
• Compare each temperature with MIN and update MIN if a lower value is found.
• Compare each temperature with MAX and update MAX if a higher value is found.
• Use a selection statement to identify night-time readings and add them to the night-time total.
• Calculate the mean temperature and mean night-time temperature outside the loop.

Example pseudocode:

TOTAL = 0
NIGHT_TOTAL = 0
MIN = 1000
MAX = -1000

loop T from 0 to 23
    NEXT = TEMP[T]

    TOTAL = TOTAL + NEXT

    if TIME[T] >= 19:00 AND TIME[T] < 07:00 then
        NIGHT_TOTAL = NIGHT_TOTAL + NEXT
    end if

    if NEXT < MIN then
        MIN = NEXT
    end if

    if NEXT > MAX then
        MAX = NEXT
    end if
end loop

MEAN_TEMP = TOTAL / 24
MEAN_NIGHT_TEMP = NIGHT_TOTAL / 12

Explanation: The loop processes all 24 hourly readings. Every temperature contributes to the overall total, while only readings belonging to the night period contribute to NIGHT_TOTAL. The minimum and maximum values are updated whenever a smaller or larger temperature is encountered. The two mean values are calculated after the loop because all required readings must first be processed.