Lengths of pregnancies (in humans) have a mean of 267.6 days and a standard deviation of 15.4 days. A woman tracked her pregnancy and found it to be 309 days. Find the z score for 309 days. Is such a length unusual?

The z-score is  

The length of days is not unusual

Step-by-step explanation:

From the question we are told that

     The population mean is  

     The standard deviation is  

      The value considered is  

The z-score is mathematically represented as

Now given that the z-score is not greater than 3  then we can say that the length of days is not unusual

(reference khan academy)

2 and 1.

step-by-step explanation:

plug in each answer. 0 doesn't work, 1 does. so does 2. 4 doesn't:

0 = 1 is not true.

2 = 2 is true.

4 = 4 is true.

8 = 16 is not true.

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