Question

  A concrete mix is designed to withstand 3000 pounds per square inch​ (psi) of pressure. The following data represent the strength of nine randomly selected casts​ (in psi). ​3970 4090 3000 2950 3840 4090 4040 3490 Compute the​ mean, median and mode strength of the concrete​ (in psi).

Answer 1

Mean value is

The median is the middle number in a sorted list of numbers. So, to find the median, we need to place the numbers in value order and find the middle number.

Ordering the data from least to greatest, we get:

2950   3000   3490   3840   3970   4040   4090   4090   

As you can see, we do not have just one middle number but we have a pair of middle numbers, so the median is the average of these two numbers:

Median=

The mode of a set of data is the value in the set that occurs most often.

Ordering the data from least to greatest, we get:

2950   3000   3490   3840   3970   4040   4090   4090   

We see that the mode is 4090 .