Khi kiểm định chi trung bình hai khu như nhau, mức ý nghĩa 5%
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Answer:
The z score for bolt of diameter 18.12 mm is 1.20.
Step-by-step explanation:
Let <em>X</em> = diameter of bolts.
It is provided that the random variable <em>X</em> follows a Normal distribution with mean, <em>μ</em> = 18 mm and standard deviation, <em>σ</em> = 0.10 mm.
A <em>z</em>-score is a standardized score, a numerical, that defines how far a data value from the mean.
The distribution of <em>z</em>-scores is defined by the Standard Normal distribution.
The formula to compute the <em>z</em>-score is:
The value of the diameter of a bolt is, <em>x</em> = 18.12 mm.
Compute the <em>z</em>-score for this value as follows:
Thus, the z score for bolt of diameter 18.12 mm is 1.20.