Igf The data set Igf contains measurements on people of various ages. The main variable of interest is the level of insulin-like growth factor (igƒ) (J. Clin. Endocrinol. Metab. 78(3): 744–752, March 1994). Each row in the data set corresponds to one individual. Data were collected on these variables:

1. Using appropriate graphics and summary statistics, describe the distribution of igƒ.

2. Describe the relationship between igƒ and sex.

3. Describe the relationship between igƒ and age using both graphics and summary statistics.

4. Is a linear regression appropriate for modeling the relationship between igƒ and age?

Transcribed Image Text:

quantitative (years, decimal) categorical (M=male; F=female) quantitative (insulin-like growth factor, µg/l) ordered categorical (codes 1-5: stages of puberty, as defined by Tanner) age sex igf tanner testvol quantitative (testicular volume, ml) menarche categorical (Has menarche (menstruation) occurred? yes/no) weight quantitative (kg) height quantitative (cm)