Question

Mean number of cell phone calls made or received per day by cell phone users. In a survey of 1917 cell phone users, the mean was 13.10 phone calls a day.

Short answer

The total number of calls made or received per day by these 1917 cell phone users is 25112.70. This total divided by the number of users gives the mean number of calls per day, which is 13.10.

Step-by-step solution

Understand the Concept of Mean

The mean is simply the sum of the numbers divided by the count of the numbers. In this case, we're given the mean and the count, but not the sum.

Calculate the Total Sum

The mean of 13.10 calls per day came from the total number of calls made by these 1917 users. To calculate that total, you multiply the mean by the count. So, the total number of calls made by the users is \(13.10 \times 1917\).

Interpret the Results

The result you get is the total number of calls that these 1917 users make in a day. Remember, the mean is the typical or 'average' number of calls that a user makes in a day. Thus, the total number of calls divided by the number of users will give the mean number of calls, which we know is 13.10.