Biology and Environmental Science
Rice is a staple food for much of the world's population. The height of a rice plant (usually 0.4-5 mm) depends on the rice variety and the environment. Genetic engineering is currently underway to protect rice plants from disease and to decrease the variability in plant height. In a controlled experiment, plant heights were measured (in millimeters); 30 natural rice plants had a sample variance in height of 1.5 mm, and 22 genetically engineered rice plants had a sample variance in height of 0.89 mm. Assume normality.
a. Find a 95% confidence interval for the true variance in height for natural rice plants.
b. Find a 95% confidence interval for the true variance in height for genetically engineered rice plants.
c. Is there any evidence to suggest the population variance is different for natural and genetically engineered rice plants?