If the pH level of the reservoir is ok, the results at each location will have varying results, with an average pH of 8.5 and a standard deviation of 0.22. If the pH level of the reservoir is ok, what is the probability that the sample average is LESS than 8.47

44.43% probability that the sample average is LESS than 8.47

Step-by-step explanation:

Problems of normally distributed samples are solved using the z-score formula.

In a set with mean and standard deviation , the zscore of a measure X is given by:

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

In this problem, we have that:

If the pH level of the reservoir is ok, what is the probability that the sample average is LESS than 8.47

This is the pvalue of Z when X = 8.47. So

has a pvalue of 0.4443.

44.43% probability that the sample average is LESS than 8.47

x = 23.78

step-by-step explanation: