The management of a supermarket wanted to study the spending habits of its male and female customers. A random sample of 16 male customers who shopped at this supermarket showed that they spent an average of $55 with a standard deviation of $12. Another random sample of 25 female customers showed that they spent $85 with a standard deviation of $20.50. Assuming that the amounts spent at this supermarket by all its male and female customers were approximately normally distributed, construct a 90% confidence interval for the ratio of variance in spending for males and females, σ12 / s22.