Math Problem Statement

Research question 1: We wish to investigate whether employment status in the Sydney region is distributed according to the table below.

employment status | Casual | Full-time | Part-time | Unemployed

Percentage        |     30 |        50 |        10 |         10

QUESTIONS:

Report the number of the degrees of freedom [integer]:

Answer 1 Question 1

Report the value of the test statistic [use at least 2dp]:

Answer 2 Question 1

Report the 

𝑝

p

-value [use at least 3dp]:

Answer 3 Question 1

We wish to investigate whether employment status in the Sydney region is distributed according to the table below. employment status | Casual | Full-time | Part-time | Unemployed Percentage | 30 | 50 | 10 | 10

Solution

To investigate whether employment status is distributed according to the provided percentages, we can perform a chi-square goodness-of-fit test. The observed values are from the contingency table in the image, and we will calculate the expected values using the given percentages. Here is the procedure and solution:

Step 1: Observed Values (from the contingency table)

The total sum of individuals is 104, and the observed values for employment status are:

  • Casual: 23
  • Full-time: 20
  • Part-time: 31
  • Unemployed: 30

Step 2: Expected Values (based on provided percentages)

We use the percentages given for each employment status to calculate the expected counts:

  • Casual (30% of 104) = 0.3×104=31.20.3 \times 104 = 31.2
  • Full-time (50% of 104) = 0.5×104=52.00.5 \times 104 = 52.0
  • Part-time (10% of 104) = 0.1×104=10.40.1 \times 104 = 10.4
  • Unemployed (10% of 104) = 0.1×104=10.40.1 \times 104 = 10.4

Step 3: Chi-square Test Statistic Calculation

The chi-square test statistic is calculated using the formula: χ2=(OE)2E\chi^2 = \sum \frac{(O - E)^2}{E} where OO is the observed value, and EE is the expected value.

Let's calculate each component:

  1. Casual: (2331.2)231.2=(8.2)231.2=67.2431.2=2.1551\frac{(23 - 31.2)^2}{31.2} = \frac{(-8.2)^2}{31.2} = \frac{67.24}{31.2} = 2.1551
  2. Full-time: (2052.0)252.0=(32)252.0=102452.0=19.6923\frac{(20 - 52.0)^2}{52.0} = \frac{(-32)^2}{52.0} = \frac{1024}{52.0} = 19.6923
  3. Part-time: (3110.4)210.4=20.6210.4=424.3610.4=40.8058\frac{(31 - 10.4)^2}{10.4} = \frac{20.6^2}{10.4} = \frac{424.36}{10.4} = 40.8058
  4. Unemployed: (3010.4)210.4=19.6210.4=384.1610.4=36.9423\frac{(30 - 10.4)^2}{10.4} = \frac{19.6^2}{10.4} = \frac{384.16}{10.4} = 36.9423

Adding these values: χ2=2.1551+19.6923+40.8058+36.9423=99.5955\chi^2 = 2.1551 + 19.6923 + 40.8058 + 36.9423 = 99.5955

Step 4: Degrees of Freedom

The degrees of freedom for a chi-square goodness-of-fit test is df=k1\text{df} = k - 1, where kk is the number of categories. Here, k=4k = 4, so: df=41=3\text{df} = 4 - 1 = 3

Step 5: pp-value Calculation

Using the chi-square distribution table or a calculator with χ2=99.5955\chi^2 = 99.5955 and 3 degrees of freedom, we find that the pp-value is extremely small, essentially p<0.001p < 0.001, indicating strong evidence against the null hypothesis.

Final Answers

  1. Degrees of Freedom: 3
  2. Test Statistic: 99.60
  3. pp-value: <0.001

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Math Problem Analysis

Mathematical Concepts

Statistics
Chi-Square Test
Goodness-of-Fit Test

Formulas

Chi-square test statistic formula: χ² = Σ ((O - E)² / E)

Theorems

Chi-square goodness-of-fit test

Suitable Grade Level

Grades 11-12 or Undergraduate