Assume that all variable are approximately normally distributed.

Hospital Noise Levels For a sample of 24 operating rooms taken in the hospital study mentioned in Exercise 19 in Section 7–1, the mean noise level was 41.6 decibels, and the standard deviation was 7.5. Find the 95% confidence interval of the true mean of the noise levels in the operating rooms.

Source: M. Bayo.. A. Garcia, and A. Garcia. “Noise Levels in an Urban Hospital and Workers’ Subjective Responses.” Archives of Environmental Health 50. no. 3. p. 249 (May–June 1995). Reprinted with permission of the Helen Dwight Reid Educational Foundation. Published by Heldref Publications. 1319 Eighteenth St. N. W., Washington, D.C. 20036-1802. Copyright © 1995.

Step 1 of 2:

From the given problem, we have

The sample size n = 24

The mean

The standard deviation

The confidence interval = 95% = 0.95.

We have to find the 95% confidence interval of the true mean of the noise levels in the operating rooms.