Suppose a brewery has a filling machine that fills 12 ounce bottles of beer. It is known that the amount of beer poured by this filling machine follows a normal distribution with a mean of 12.4 ounces and a standard deviation of 0.04 ounce. Find the probability that the bottle contains between 12.3 and 12.36 ounces.

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Answer:

15.25% probability that the bottle contains between 12.3 and 12.36 ounces.

Step-by-step explanation:

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

In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the zscore of a measure X is given by:

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

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:

[tex]\mu = 12.4, \sigma = 0.04[/tex]

Find the probability that the bottle contains between 12.3 and 12.36 ounces.

This is the pvalue of Z when X = 12.36 subtracted by the pvalue of Z when X = 12.3

X = 12.36

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

[tex]Z = \frac{12.36 - 12.4}{0.04}[/tex]

[tex]Z = -1[/tex]

[tex]Z = -1[/tex] has a pvalue of 0.1587

X = 12.3

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

[tex]Z = \frac{12.3 - 12.4}{0.04}[/tex]

[tex]Z = -2.5[/tex]

[tex]Z = -2.5[/tex] has a pvalue of 0.0062

0.1587 - 0.0062 = 0.1525

15.25% probability that the bottle contains between 12.3 and 12.36 ounces.