Researchers wanted to determine if there was an association between daily cantaloupe consumption and the occurrence of high cholesterol. The researchers looked at 93 comma 029 women and asked them to report their cantaloupe​-eating habits. The researchers also determined which of the women had high cholesterol. After their​ analysis, the researchers concluded that consumption of two or more servings of cantaloupe per day was associated with a reduction in high cholesterol. Complete parts​ (a) through​ (c) below.

In their​ report, the researchers stated that​ "After adjusting for various demographic and lifestyle​ variables, daily consumption of two or more servings was associated with a​ 30% reduced prevalence of high cholesterol​." Why was it important to adjust for these​ variables?