9.1 Hypothesis Testing for One Mean

9.1.1 Case 1: Known Population Standard Deviation

Stat > Basic Statistics > 1-Sample Z

Example 9.1:

A filling line of detergent packages must introduce 4 kg in each package. A sample of 20 units is taken and subsequently weighted (in grams) obtaining the following measures:

Historical data indicate a standard deviation of the weights of 25 g. Check if the process is not centred; that is, check if the mean of the packets’ weights is different from the target value of 4 kg.

Enter the data in column C1 and call it ‘Weights’. Then, go to Stat > Basic Statistics > 1-Sample Z:

With all default options, the output is the following:

The options are:

Notice that the button Graphs allows you to select any of the following graphs:

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