Question One

Setting a work directory

Import data

(a)

Plot

## Comment ### Looking at the numbers, as income increases, expenditure also seems to increase, but not perfectly. For example, income 30 corresponds to expenditure 9, income 33 to 8 (which is a slight decrease), then 40 to 11. So there might be a general upward trend but with some variability. The plot might show a positive correlation, but maybe not very strong. I should check for outliers or any non-linear patterns. Since the income ranges from 13 to 43 and expenditure from 4 to 11, the plot should spread across that range. Maybe the relationship is roughly linear? That’s what I need for regression. So in the plot, I can comment on the direction (positive), form (linear?), strength (moderate?), and any unusual features.

(b)

## 
## Call:
## lm(formula = expenditure ~ income)
## 
## Residuals:
##      Min       1Q   Median       3Q      Max 
## -0.87148 -0.66518 -0.03357  0.69345  0.78137 
## 
## Coefficients:
##             Estimate Std. Error t value Pr(>|t|)    
## (Intercept)  2.17266    0.72022   3.017   0.0166 *  
## income       0.20230    0.02327   8.692 2.39e-05 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 0.733 on 8 degrees of freedom
## Multiple R-squared:  0.9043, Adjusted R-squared:  0.8923 
## F-statistic: 75.56 on 1 and 8 DF,  p-value: 2.391e-05

For each additional dollar of income, food expenditure increases by approximately 0.202 dollars per week. The intercept suggests that if income were zero, the expected expenditure is $2.18, which might not make practical sense but is part of the model.

Assignment

Germano Nyaga

2025-03-03

Question One

Setting a work directory

Import data

(a)

Plot

(b)

For each additional dollar of income, food expenditure increases by approximately 0.202 dollars per week. The intercept suggests that if income were zero, the expected expenditure is $2.18, which might not make practical sense but is part of the model.

(c)