(a) Fit a model with just size of firm as independent variable (Modell). (b) Interpret the coefficients in Modell (c) Fit a regression model with size and type of firm as independent variables (Model2) (d) With a proper plot show the effect of different type of firm on the number of months elapsed (e) Make proper interpretation based on the coefficients in Model2. (f) Run a significant test for the difference of number of months elapsed for different type of firm (mutual, stock) at level 0.05. Also find a 95% CI and interpret it. (g) Based on model 2, estimate the number of months elapsed for a firm with size 200 and type stock. Also find 90% CI and PI for it.
![**4.20 Neter, Kutner, Nachtsheim, and Wasserman (1996) Study**
This study explores the relationship between the speed (y) at which an insurance innovation is adopted, the size of the firm (x), and the type of firm. The dependent variable y is the number of months between when the first firm adopted the innovation and when a particular firm adopted it. The firm's size x is measured in total assets (in millions), and the firm type is either mutual or stock.
**Data Table:**
- **Columns:**
- **Number of Months Elapsed (y):** Time elapsed in months since the innovation was first adopted.
- **Size of Firm (x, in millions):** Total assets of the firm.
- **Type of Firm:** Indicates if the firm is mutual or stock.
**Data Entries:**
- Firms 1 to 10 are of "Mutual" type, and their elapsed months range from 17 to 16, with firm sizes from 151 to 290 million.
- Firms 11 to 20 are of "Stock" type, and their elapsed months range from 28 to 14, with firm sizes from 164 to 305 million.
**Tasks:**
(a) Fit a model using only firm size as the independent variable (Model 1).
(b) Interpret the coefficients in Model 1.
(c) Create a regression model with firm size and type as independent variables (Model 2).
(d) Plot showing the effect of firm type on the number of months elapsed.
(e) Interpret the coefficients in Model 2.
(f) Test for significant differences in months elapsed between mutual and stock firms at a 0.05 significance level, and find a 95% confidence interval (CI).
(g) Estimate months elapsed for a firm with size 200 and type stock using Model 2, including 90% CI and prediction interval (PI).
(h) Develop a model with size, type, and their interaction as variables (Model 3).
(i) Interpret the coefficients in Model 3.
(j) Perform a partial F-test comparing Model 2 (complete) to Model 1 (reduced) at a 0.05 level.
This structured approach allows for understanding the impact of firm size and type on the adoption speed of innovations within insurance companies.](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2Fb9e27b5d-0ab8-428e-954d-97d64fc14c61%2F5a7c2c34-75b3-490f-8969-9455b4dd2a12%2Fmmbti3k_processed.png&w=3840&q=75)
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Since you have posted a question with multiple subparts, we will provide solution to the first three sub-parts as per our Q&A guidelines. Please repost the remaining sub parts separately.
a) After entering the data in Excel go to Data>Data Analysis>Regression>choose the input range for Y and X and tick the "Labels" box>click "OK".
You get the following output:
SUMMARY OUTPUT | ||||||||
Regression Statistics | ||||||||
Multiple R | 0.840777 | |||||||
R Square | 0.706906 | |||||||
Adjusted R Square | 0.690623 | |||||||
Standard Error | 5.231489 | |||||||
Observations | 20 | |||||||
ANOVA | ||||||||
df | SS | MS | F | Significance F | ||||
Regression | 1 | 1188.167 | 1188.167 | 43.41371 | 3.45E-06 | |||
Residual | 18 | 492.6326 | 27.36848 | |||||
Total | 19 | 1680.8 | ||||||
Coefficients | Standard Error | t Stat | P-value | Lower 95% | Upper 95% | Lower 95.0% | Upper 95.0% | |
Intercept | 36.4821 | 2.844252 | 12.82661 | 1.71E-10 | 30.50656 | 42.45767 | 30.50656 | 42.45767 |
x | -0.0939 | 0.014257 | -6.58891 | 3.45E-06 | -0.12389 | -0.06398 | -0.12389 | -0.06398 |
The equation of model 1 is:
, where
is the predicted number of months elapsed and x is the size of the firm (in millions).
b) In model 1, intercept = 36.4821 which is the average number of months elapsed for a firm with size of 0 million.
The slope coefficient is -0.0939. It means that for every extra million in size of the firm, the number of months elapsed decreases by 0.0939, on average.
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