’n Kriminoloog glo dat reënweer misdaadvlakke beïnvloed. Die tabel hieronder gee die aantal dae wat dit gereën het en die aantal misdade wat gerapporteer is gedurende Mei van 2005 tot 2009. / A criminologist believes that rainy weather influences crime levels. The table below shows the number of rainy days and number of crimes reported in May from 2005 to 2009.
| 2005 | 2006 | 2007 | 2008 | 2009 |
Aantal reëndae / Number of rainy days | 7 | 15 | 10 | 8 | 22 |
Aantal misdade / Number of crimes | 31 | 46 | 29 | 38 | 15 |
Die beraamde waarde vir die helling is / The estimated value of the slope is
Watter een van die volgende is nie ʼn aanname vir enkelvoudige lineêre regressie nie? / Which of the following is not an assumption for simple linear regression?
Aanvaar ’n lineêre verwantskap tussen X en Y. Indien die korrelasiekoëffisiënt r = -0.4, dan / Assume a linear relationship between X and Y. If the correlation coefficient r = -0.4, then
Beskou die lineêre model hieronder: / Consider the linear model below:
Voorspel die gemiddelde van Y vir X = 7.5. / Predict the mean of Y for X = 7.5.
ʼn Bemarker ondersoek die verwantskap tussen die bedrag spandeer op advertensies en die verkope van ʼn spesifieke produk. Verkope en die uitgawe op advertensies data is beskikbaar vir die afgelope tien maande (in R’000). / A marketer investigates the relationship between the amount spent on advertising and the sales of a specific product. Sales figures and advertising expenses for the past ten months (in R’000) are available.
Maand Month | Verkope Sales (Y) | Advertensie Advertising (X) | Maand Month | Verkope Sales (Y) | Advertensie Advertising (X) |
1 | 85 | 33 | 6 | 103 | 50 |
2 | 123 | 60 | 7 | 115 | 50 |
3 | 122 | 60 | 8 | 93 | 35 |
4 | 99 | 43 | 9 | 112 | 53 |
5 | 95 | 40 | 10 | 111 | 56 |
Bereken die bepaaldheidskoëffisiënt. / Determine the coefficient of determination.
ʼn Bemarker ondersoek die verwantskap tussen die bedrag spandeer op advertensies en die verkope van ʼn spesifieke produk. Verkope en die uitgawe op advertensies data is beskikbaar vir die afgelope tien maande (in R’000). / A marketer investigates the relationship between the amount spent on advertising and the sales of a specific product. Sales figures and advertising expenses for the past ten months (in R’000) are available.
Maand Month | Verkope Sales (Y) | Advertensie Advertising (X) | Maand Month | Verkope Sales (Y) | Advertensie Advertising (X) |
1 | 85 | 33 | 6 | 103 | 50 |
2 | 123 | 60 | 7 | 115 | 50 |
3 | 122 | 60 | 8 | 93 | 35 |
4 | 99 | 43 | 9 | 112 | 53 |
5 | 95 | 40 | 10 | 111 | 56 |
Bereken die kovariansie. / Calculate the covariance.