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The table shows the wages in US dollars earned by technical developers in an ICT firm. Given that the mean wage is 27 rac1116 USD, find the value of a.

Mathematics

ScanSolve AI Answer

Answers

2 parts
a
3
b
15 - 24
16

Step-by-step solution

7 steps

here's the solution for question 17.

Part 17

The table below shows the wages in US dollars earned by technical developers in an ICT firm.

Amount (USD)10 - 1415 - 2425 - 2930 - 4445 - 64
Number of workers616a105

Part a3

Given that the mean wage is 27111627 \frac{11}{16} USD, find the value of a.

  1. Calculate the midpoint (xx) for each class.

    For grouped data, the mean is given by the formula: Mean=∑(f×x)∑f\text{Mean} = \frac{\sum (f \times x)}{\sum f}.

    Class (Amount USD)Frequency (ff)Midpoint (xx)f×xf \times x
    10 - 14610+142=12\frac{10+14}{2} = 126×12=726 \times 12 = 72
    15 - 241615+242=19.5\frac{15+24}{2} = 19.516×19.5=31216 \times 19.5 = 312
    25 - 29a25+292=27\frac{25+29}{2} = 27a×27=27aa \times 27 = 27a
    30 - 441030+442=37\frac{30+44}{2} = 3710×37=37010 \times 37 = 370
    45 - 64545+642=54.5\frac{45+64}{2} = 54.55×54.5=272.55 \times 54.5 = 272.5
  2. Calculate the sum of frequencies (∑f\sum f) and the sum of (f×xf \times x) (∑(f×x)\sum (f \times x)).

    ∑f=6+16+a+10+5=37+a\sum f = 6 + 16 + a + 10 + 5 = 37 + a ∑(f×x)=72+312+27a+370+272.5=1026.5+27a\sum (f \times x) = 72 + 312 + 27a + 370 + 272.5 = 1026.5 + 27a
  3. Set up the equation for the mean.

    The given mean wage is 27111627 \frac{11}{16} USD.

    271116=27×16+1116=432+1116=4431627 \frac{11}{16} = \frac{27 \times 16 + 11}{16} = \frac{432 + 11}{16} = \frac{443}{16}

    Using the mean formula:

    1026.5+27a37+a=44316\frac{1026.5 + 27a}{37 + a} = \frac{443}{16}
  4. Solve for aa.

    Cross-multiply:

    16(1026.5+27a)=443(37+a)16(1026.5 + 27a) = 443(37 + a) 16424+432a=16391+443a16424 + 432a = 16391 + 443a

    Subtract 432a432a from both sides:

    16424=16391+443a−432a16424 = 16391 + 443a - 432a 16424=16391+11a16424 = 16391 + 11a

    Subtract 16391 from both sides:

    16424−16391=11a16424 - 16391 = 11a 33=11a33 = 11a a=3311a = \frac{33}{11} a=3a = 3

    The value of aa is 3\boxed{3}.

Part b15 - 24

Find the median class and its frequency.

  1. Use the value of a=3a=3 to list the frequencies and calculate the total number of workers.

    Frequencies: 6, 16, 3, 10, 5.
    Total number of workers (∑f\sum f) =6+16+3+10+5=40= 6 + 16 + 3 + 10 + 5 = 40.

  2. Determine the position of the median.

    The median position is ∑f2=402=20th\frac{\sum f}{2} = \frac{40}{2} = 20^{\text{th}} value.

  3. Calculate the cumulative frequencies to find the median class.

    Class (Amount USD)Frequency (ff)Cumulative Frequency (cf)
    10 - 1466
    15 - 24166+16=226 + 16 = 22
    25 - 29322+3=2522 + 3 = 25
    30 - 441025+10=3525 + 10 = 35
    45 - 64535+5=4035 + 5 = 40

    The 20th20^{\text{th}} value falls into the class where the cumulative frequency first exceeds or equals 20. This is the class 15 - 24, which has a cumulative frequency of 22.

    The median class is 15−24\boxed{15 - 24}.
    The frequency of the median class is 16\boxed{16}.

Part c

On the grid provided, draw a histogram to represent the information.

To draw a histogram for this data, you would follow these steps:

  1. Determine Class Boundaries: Adjust the class intervals to be continuous. For example, 10-14 becomes 9.5-14.5, 15-24 becomes 14.5-24.5, and so on.
  2. Calculate Class Widths: The width of each class interval (e.g., 14.5−9.5=514.5 - 9.5 = 5).
  3. Calculate Frequency Densities: Since the class widths are not uniform, you need to calculate frequency density for each class using the formula: Frequency Density=FrequencyClass Width\text{Frequency Density} = \frac{\text{Frequency}}{\text{Class Width}}.
    • 10-14: 65=1.2\frac{6}{5} = 1.2
    • 15-24: 1610=1.6\frac{16}{10} = 1.6
    • 25-29: 35=0.6\frac{3}{5} = 0.6
    • 30-44: 1015≈0.67\frac{10}{15} \approx 0.67
    • 45-64: 520=0.25\frac{5}{20} = 0.25
  4. Draw Axes: The x-axis represents the Amount (USD) using the class boundaries. The y-axis represents the Frequency Density.
  5. Draw Bars: For each class, draw a rectangular bar with a width corresponding to its class width and a height corresponding to its frequency density. The bars should touch each other.
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