The pH measurements of water specimens from various locations along a given river basin are Normally distributed with mean 8 and standard deviation 0.3.
Three-fourths of the pH measurements in this river are greater than the value

Question

Quizplus · Accepted Answer

Given that the pH measurements are normally distributed with a mean of 8 and a standard deviation of 0.3, and that three-fourths of the measurements are greater than the value in question, this implies that the value is at the first quartile (Q1) of the distribution. The first quartile is one standard deviation below the mean in a normal distribution, which calculates to 8 - 0.3 = 7.7. However, the exact calculation for the Z-score corresponding to the 25th percentile (Q1) in a standard normal distribution is approximately -0.6745. Applying this to the given mean and standard deviation, the exact value isn't provided, but the closest and most reasonable option given the context is 7.798.

The PH Measurements of Water Specimens from Various Locations Along