
Consider the following time series data:
Using the naïve method (most recent value) as the forecast for the next week, compute the following measures of forecast accuracy:
- a.
Mean absolute error - b. Mean squared error
- c. Mean absolute percentage error
- d. What is the forecast for week 7?
(a)

Find the value of mean absolute error.
Answer to Problem 1P
The mean absolute error is 4.4.
Explanation of Solution
Week | Time Series Value | Forecast | Forecast Error | Absolute Value of Forecast Error |
1 | 18 | |||
2 | 13 | 18 | −5 | 5 |
3 | 16 | 13 | 3 | 3 |
4 | 11 | 16 | −5 | 5 |
5 | 17 | 11 | 6 | 6 |
6 | 14 | 17 | −3 | 3 |
Total | 22 |
Thus, the mean absolute error is 4.4.
(b)

Obtain the mean squared error.
Answer to Problem 1P
The mean squared error is 20.8.
Explanation of Solution
The mean squared error is obtained as given below:
Absolute Value of Forecast Error | Squared Forecast Error |
5 | 25 |
3 | 9 |
5 | 25 |
6 | 36 |
3 | 9 |
22 | 104 |
Thus, the mean squared error is 20.8.
(c)

Find the mean absolute percentage error.
Answer to Problem 1P
The mean absolute percentage error is 31.88.
Explanation of Solution
The mean absolute percentage error is obtained is given below:
Week | Time Series Value | Forecast | Forecast Error | Percentage Error | Absolute percentage Error |
1 | 18 | ||||
2 | 13 | 18 | −5 | −38.46 | 38.46 |
3 | 16 | 13 | 3 | 18.75 | 18.75 |
4 | 11 | 16 | −5 | −45.45 | 45.45 |
5 | 17 | 11 | 6 | 35.29 | 35.29 |
6 | 14 | 17 | −3 | −21.43 | 21.43 |
Total | −51.30 | 159.38 |
Thus, the mean absolute percentage error is 31.88.
(d)

Obtain the forecast for week 7.
Answer to Problem 1P
The forecast for week 7 is 14.
Explanation of Solution
The forecast for week 7 is obtained as given below:
Thus, the forecast for week 7 is 14.
Want to see more full solutions like this?
Chapter 8 Solutions
Essentials of Business Analytics (MindTap Course List)
- Examine the Variables: Carefully review and note the names of all variables in the dataset. Examples of these variables include: Mileage (mpg) Number of Cylinders (cyl) Displacement (disp) Horsepower (hp) Research: Google to understand these variables. Statistical Analysis: Select mpg variable, and perform the following statistical tests. Once you are done with these tests using mpg variable, repeat the same with hp Mean Median First Quartile (Q1) Second Quartile (Q2) Third Quartile (Q3) Fourth Quartile (Q4) 10th Percentile 70th Percentile Skewness Kurtosis Document Your Results: In RStudio: Before running each statistical test, provide a heading in the format shown at the bottom. “# Mean of mileage – Your name’s command” In Microsoft Word: Once you've completed all tests, take a screenshot of your results in RStudio and paste it into a Microsoft Word document. Make sure that snapshots are very clear. You will need multiple snapshots. Also transfer these results to the…arrow_forwardExamine the Variables: Carefully review and note the names of all variables in the dataset. Examples of these variables include: Mileage (mpg) Number of Cylinders (cyl) Displacement (disp) Horsepower (hp) Research: Google to understand these variables. Statistical Analysis: Select mpg variable, and perform the following statistical tests. Once you are done with these tests using mpg variable, repeat the same with hp Mean Median First Quartile (Q1) Second Quartile (Q2) Third Quartile (Q3) Fourth Quartile (Q4) 10th Percentile 70th Percentile Skewness Kurtosis Document Your Results: In RStudio: Before running each statistical test, provide a heading in the format shown at the bottom. “# Mean of mileage – Your name’s command” In Microsoft Word: Once you've completed all tests, take a screenshot of your results in RStudio and paste it into a Microsoft Word document. Make sure that snapshots are very clear. You will need multiple snapshots. Also transfer these results to the…arrow_forward2 (VaR and ES) Suppose X1 are independent. Prove that ~ Unif[-0.5, 0.5] and X2 VaRa (X1X2) < VaRa(X1) + VaRa (X2). ~ Unif[-0.5, 0.5]arrow_forward
- 8 (Correlation and Diversification) Assume we have two stocks, A and B, show that a particular combination of the two stocks produce a risk-free portfolio when the correlation between the return of A and B is -1.arrow_forward9 (Portfolio allocation) Suppose R₁ and R2 are returns of 2 assets and with expected return and variance respectively r₁ and 72 and variance-covariance σ2, 0%½ and σ12. Find −∞ ≤ w ≤ ∞ such that the portfolio wR₁ + (1 - w) R₂ has the smallest risk.arrow_forward7 (Multivariate random variable) Suppose X, €1, €2, €3 are IID N(0, 1) and Y2 Y₁ = 0.2 0.8X + €1, Y₂ = 0.3 +0.7X+ €2, Y3 = 0.2 + 0.9X + €3. = (In models like this, X is called the common factors of Y₁, Y₂, Y3.) Y = (Y1, Y2, Y3). (a) Find E(Y) and cov(Y). (b) What can you observe from cov(Y). Writearrow_forward
- 1 (VaR and ES) Suppose X ~ f(x) with 1+x, if 0> x > −1 f(x) = 1−x if 1 x > 0 Find VaRo.05 (X) and ES0.05 (X).arrow_forwardJoy is making Christmas gifts. She has 6 1/12 feet of yarn and will need 4 1/4 to complete our project. How much yarn will she have left over compute this solution in two different ways arrow_forwardSolve for X. Explain each step. 2^2x • 2^-4=8arrow_forward
- One hundred people were surveyed, and one question pertained to their educational background. The results of this question and their genders are given in the following table. Female (F) Male (F′) Total College degree (D) 30 20 50 No college degree (D′) 30 20 50 Total 60 40 100 If a person is selected at random from those surveyed, find the probability of each of the following events.1. The person is female or has a college degree. Answer: equation editor Equation Editor 2. The person is male or does not have a college degree. Answer: equation editor Equation Editor 3. The person is female or does not have a college degree.arrow_forwardneed help with part barrow_forwardSuppose you know that Bob's test score is above the mean, but he doesn't remember by how much. At least how many students must score lower than Bob?arrow_forward
- Glencoe Algebra 1, Student Edition, 9780079039897...AlgebraISBN:9780079039897Author:CarterPublisher:McGraw HillCollege Algebra (MindTap Course List)AlgebraISBN:9781305652231Author:R. David Gustafson, Jeff HughesPublisher:Cengage LearningHolt Mcdougal Larson Pre-algebra: Student Edition...AlgebraISBN:9780547587776Author:HOLT MCDOUGALPublisher:HOLT MCDOUGAL
- Big Ideas Math A Bridge To Success Algebra 1: Stu...AlgebraISBN:9781680331141Author:HOUGHTON MIFFLIN HARCOURTPublisher:Houghton Mifflin HarcourtFunctions and Change: A Modeling Approach to Coll...AlgebraISBN:9781337111348Author:Bruce Crauder, Benny Evans, Alan NoellPublisher:Cengage LearningTrigonometry (MindTap Course List)TrigonometryISBN:9781305652224Author:Charles P. McKeague, Mark D. TurnerPublisher:Cengage Learning





