3.9795 ± 3.707(.6529) = (1.56, 6.40). We are 99% confident that the true slope of the population
regression line lies between 1.56 and 6.40.
a. This is a geometric distribution problem. The probability that the first success occurs on the 10th
roll is given by G (10) = (0.083)(1 – 0.083) = 0.038. (On the TI-83/84, G (10) =
geometpdf(0.083,10)=0.038.)
b. . On average, it will take about 12 rolls before you get a 10. (Actually, it’s exactly
12 rolls on average since the exact probability of rolling a 10 is , not 0.083, and
This is an example of a matched pairs design . The identical twins form a block for comparison of
the treatment. Statistics are based on the differences between the scores of the pairs of twins. Hence
this is a one-variable situation—one population of values, each constructed as a difference of the
matched pairs.
- a. Residual = actual – predicted = 3.8 – [–0.826 + 0.193(25.5)] = 3.8 – 4.096 = −0.296.
b. There does not seem to be any consistent pattern in the residual plot, indicating that a line is
probably a good model for the data.