A note on the turning point for the quadratic trend
The quadratic trend is a statistical model described by the quadratic function. Finding its extremum (also called the vertex or the turning point) using differential calculus or completing the square method is very well known in the literature. In this paper, a new method for finding the extremum of...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
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Croatian Statistical Association
2019-12-01
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| Series: | Croatian Review of Economic, Business and Social Statistics |
| Subjects: | |
| Online Access: | https://doi.org/10.2478/crebss-2019-0010 |
| _version_ | 1797225672942288896 |
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| author | Kojić Vedran Škrinjarić Tihana |
| author_facet | Kojić Vedran Škrinjarić Tihana |
| author_sort | Kojić Vedran |
| collection | DOAJ |
| description | The quadratic trend is a statistical model described by the quadratic function. Finding its extremum (also called the vertex or the turning point) using differential calculus or completing the square method is very well known in the literature. In this paper, a new method for finding the extremum of the quadratic function, based on a simple mathematical inequality is proposed. In comparison with the other two known methods, our method does not require the differentiability assumption and it takes fewer steps than completing the square method. Also, it is shown how the turning point for the quadratic trend can be applied in forecasting the unemployment rate in Croatia in the first quarter of 2019. The obtained conclusions are equal to the conclusions obtained in the usual way by using forecasting software. |
| first_indexed | 2024-03-08T07:33:55Z |
| format | Article |
| id | doaj.art-32c7ba55e1f04e9db4a96df8d1dd6dbf |
| institution | Directory Open Access Journal |
| issn | 2459-5616 |
| language | English |
| last_indexed | 2024-04-24T14:12:45Z |
| publishDate | 2019-12-01 |
| publisher | Croatian Statistical Association |
| record_format | Article |
| series | Croatian Review of Economic, Business and Social Statistics |
| spelling | doaj.art-32c7ba55e1f04e9db4a96df8d1dd6dbf2024-04-03T08:59:40ZengCroatian Statistical AssociationCroatian Review of Economic, Business and Social Statistics2459-56162019-12-0152394810.2478/crebss-2019-0010A note on the turning point for the quadratic trendKojić Vedran0Škrinjarić Tihana1Faculty of Economics and Business, University of Zagreb, CroatiaFaculty of Economics and Business, University of Zagreb, CroatiaThe quadratic trend is a statistical model described by the quadratic function. Finding its extremum (also called the vertex or the turning point) using differential calculus or completing the square method is very well known in the literature. In this paper, a new method for finding the extremum of the quadratic function, based on a simple mathematical inequality is proposed. In comparison with the other two known methods, our method does not require the differentiability assumption and it takes fewer steps than completing the square method. Also, it is shown how the turning point for the quadratic trend can be applied in forecasting the unemployment rate in Croatia in the first quarter of 2019. The obtained conclusions are equal to the conclusions obtained in the usual way by using forecasting software.https://doi.org/10.2478/crebss-2019-0010forecasting unemployment ratemathematical inequalityquadratic trendsingle-variable quadratic functionturning point (vertex)c22c61e24e27 |
| spellingShingle | Kojić Vedran Škrinjarić Tihana A note on the turning point for the quadratic trend Croatian Review of Economic, Business and Social Statistics forecasting unemployment rate mathematical inequality quadratic trend single-variable quadratic function turning point (vertex) c22 c61 e24 e27 |
| title | A note on the turning point for the quadratic trend |
| title_full | A note on the turning point for the quadratic trend |
| title_fullStr | A note on the turning point for the quadratic trend |
| title_full_unstemmed | A note on the turning point for the quadratic trend |
| title_short | A note on the turning point for the quadratic trend |
| title_sort | note on the turning point for the quadratic trend |
| topic | forecasting unemployment rate mathematical inequality quadratic trend single-variable quadratic function turning point (vertex) c22 c61 e24 e27 |
| url | https://doi.org/10.2478/crebss-2019-0010 |
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