Concept explainers
To find:Theequation of the regression line and estimating the daily purchase on day 10 of the sale.
Answer to Problem 43SGR
The equation of regression line is
Explanation of Solution
Given: Daily purchases on different days since sale begun is given.
Concept Used: The general equation for a regression line is given as:
Where, Y is dependent and X is an independent variable. Also, a is the y-intercept and b is the slope of the line.
The values of a and b can be obtained by the following formulae:
Here, n is the number of observations used to estimate the regression line.
Calculation:
The table showing all the values corresponding to each observation is shown below:
Observation | Day of Sale (
) | Daily Purchases (
) |
|
|
|
1 | 1 | 15 | 15 | 1 | 225 |
2 | 2 | 21 | 42 | 4 | 441 |
3 | 3 | 32 | 96 | 9 | 1024 |
4 | 4 | 30 | 120 | 16 | 900 |
5 | 5 | 40 | 200 | 25 | 1600 |
6 | 6 | 38 | 228 | 36 | 1444 |
7 | 7 | 51 | 357 | 49 | 2601 |
| 28 | 227 | 1058 | 140 | 8235 |
From above table,
Hence, the equation of the regression line is obtained as:
Now, Let us estimate the sale on day 10 since the sale has begun. For this,
Hence,
Conclusion:Thus, the equation of regression line is
Chapter 4 Solutions
Glencoe Algebra 1, Student Edition, 9780079039897, 0079039898, 2018
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