A school has found from past records that the average scores for boys is 75 in a sample of 45 boys and the
average scores for girls is 85 in a sample of 30 girls. The population standard deviations for boys' and girls' scores were 25 and 17, respectively. The 90% confidence interval for the difference of the population means is approximately (_____, −2.022). Assume that the distributions of the scores of men and women are normally distributed. Round your answer to three decimal places.
Find upper bound.