Number of ads versus number of sales for a retailer of satellite dishes

Data used in Exercise 9.15

Adsales

Format

A data frame/tibble with six observations on three variables

month

a character vector listing month

ads

a numeric vector containing number of ads

sales

a numeric vector containing number of sales

References

Kitchens, L. J. (2003) Basic Statistics and Data Analysis. Pacific Grove, CA: Brooks/Cole, a division of Thomson Learning.

Examples

plot(sales ~ ads, data = Adsales, main = "Exercise 9.15")
mod <- lm(sales ~ ads, data = Adsales)
abline(mod, col = "red")

summary(mod)
#> 
#> Call:
#> lm(formula = sales ~ ads, data = Adsales)
#> 
#> Residuals:
#>        1        2        3        4        5        6 
#>  0.32517 -1.35635  1.18931  0.50780  0.05345 -0.71938 
#> 
#> Coefficients:
#>             Estimate Std. Error t value Pr(>|t|)    
#> (Intercept)   4.6748     0.8018   5.831 0.004311 ** 
#> ads           1.2272     0.1176  10.437 0.000476 ***
#> ---
#> Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1
#> 
#> Residual standard error: 1.017 on 4 degrees of freedom
#> Multiple R-squared:  0.9646,	Adjusted R-squared:  0.9557 
#> F-statistic: 108.9 on 1 and 4 DF,  p-value: 0.0004761
#> 
predict(mod, newdata = data.frame(ads = 6), interval = "conf", level = 0.99)
#>        fit      lwr      upr
#> 1 12.03786 10.12395 13.95177