Table of contents
- 1. Intro to Stats and Collecting Data55m
- 2. Describing Data with Tables and Graphs1h 55m
- 3. Describing Data Numerically1h 45m
- 4. Probability2h 16m
- 5. Binomial Distribution & Discrete Random Variables2h 33m
- 6. Normal Distribution and Continuous Random Variables1h 38m
- 7. Sampling Distributions & Confidence Intervals: Mean1h 3m
- 8. Sampling Distributions & Confidence Intervals: Proportion1h 12m
- 9. Hypothesis Testing for One Sample1h 1m
- 10. Hypothesis Testing for Two Samples2h 8m
- 11. Correlation48m
- 12. Regression1h 4m
- 13. Chi-Square Tests & Goodness of Fit1h 20m
- 14. ANOVA1h 0m
13. Chi-Square Tests & Goodness of Fit
Goodness of Fit Test
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A gym owner wants to know if the gym has similar numbers of members across different age groups. The table shows the distribution of ages for members from a random survey. Find the x2 statistic to test the claim that the gym has equal numbers of members of all age ranges.

A
0.92
B
0.46
C
0.08
D
0.54

1
Step 1: Calculate the total number of members surveyed by summing the values in the '# of Members' row. This will give the total sample size.
Step 2: Determine the expected frequency for each age group under the assumption that the gym has equal numbers of members across all age groups. Divide the total number of members by the number of age groups to find the expected frequency for each group.
Step 3: For each age group, calculate the difference between the observed frequency (given in the table) and the expected frequency. Square this difference to eliminate negative values.
Step 4: Divide the squared difference for each age group by the expected frequency. This step calculates the contribution of each age group to the chi-squared statistic.
Step 5: Sum all the contributions from Step 4 to find the chi-squared statistic (χ²). This value will be used to test the claim about equal distribution of members across age groups.
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