Calibrating a scale: Making sure that the scales used by businesses in the United States are accurate is the responsibility of the National Institute for Standards and Technology (NIST) in Washington, D.C. Suppose that NIST technicians are testing a scale by using a weight known to weigh exactly 1000 grams. The standard deviation for scale reading is known to be =σ2.5 . They weigh this weight on the scale 48 times and read the result each time. The 48 scale readings have a sample mean of =x998.9 grams. The calibration point is set too low if the mean scale reading is less than 1000 grams. The technicians want to perform a hypothesis test to determine whether the calibration point is set too low. Use the =α0.01 level of significance and the P -value method Compute the value of the test statistic. Round the answer to two decimal places. z =
Calibrating a scale: Making sure that the scales used by businesses in the United States are accurate is the responsibility of the National Institute for Standards and Technology (NIST) in Washington, D.C. Suppose that NIST technicians are testing a scale by using a weight known to weigh exactly
grams. The standard deviation for scale reading is known to be
. They weigh this weight on the scale
times and read the result each time. The
scale readings have a sample
grams. The calibration point is set too low if the mean scale reading is less than
grams. The technicians want to perform a hypothesis test to determine whether the calibration point is set too low. Use the
level of significance and the
-value method
Compute the value of the test statistic. Round the answer to two decimal places.
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z
=
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