(b) Test whether the factors have any main effects and whether they interact. Use a level of significance of .05 for each test. Write your ANOVA table. Present all the confidence intervals and summarize your results.

4. A computer software organization was encountering serious problems in predicting the man-day requirements for implementing large-scale programming projects. As part of a study on how to improve predic- tions, the company man-days for a large project about to be undertaken. The program- mers were given full details about the specifications for the project The programmers were classified by type of experience and amount of experience, and after the project was completed the forecasting er- rors were obtained. The forecasting errors (man-days predicted minus actual man-days) were asked 24 programmers to predict the number of Amount of Experience Type of Experience Small-scale systems only 2-5 years 100 118 Under 2 years 268 196 245 188 83 More than 5 years 46 92 58 58 38 96 47 52 31 49 Large-scale systems 68 57 42 32 DO NOT TRANSFORM the data for parts (a and b)