A random sample of 8 women resulted in systolic blood pressure levels with a mean of 121 and a standard deviation of 1.8. A random sample of 11 men resulted in systolic blood pressure levels with a mean of 138 and a standard deviation of 6.6. Use a 0.025 significance level and the critical value method to test the claim that blood pressure levels for men vary more than blood pressure levels for women.

Enter the smallest critical value. (Round your answer to nearest ten-thousandth.)