期末复习5

# 决策树

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1. SELECT DISTINCT store_id FROM Tx WHERE month = 5;
2. SELECT DISTINCT c.name FROM Tx t JOIN Tx_Cakes tc ON t.tx_id = tc.tx_id
JOIN Cake c ON tc.cake_id = c.cake_id WHERE t.month = 5;
3. SELECT t.month,SUM(t.value) AS total_value,AVG(t.value) AS avg_value,
COUNT(tc.cake_id) AS cake_sales_count FROM Tx t JOIN Tx_Cakes tc ON t.tx_id = tc.tx_id GROUP BY t.month;
4. SELECT store_id, SUM(value) AS total_sales, AVG(value) AS avg_sales
FROM Tx GROUP BY store_id HAVING AVG(value) >= 5 ORDER BY total_sales DESC
LIMIT 3;

Null Hypothesis (H₀): There is no significant difference in ant population numbers among the groups fed high-sugar, high-carbohydrate, and high-fat diets.
Statistical Test: Use one-way ANOVA (Analysis of Variance) if there are three or more diet groups. This test checks whether there are statistically significant differences in the means of the groups.
Criteria for Rejecting or Accepting H₀:1.Set a significance level (e.g., α = 0.05). 2.If the p-value ≤ 0.05, reject H₀, concluding that at least one diet significantly affects the ant population.3.If the p-value > 0.05, fail to reject H₀, concluding that there is no significant difference among the diets.