Question

Mr. Oliver, a track coach, recorded the number of runners on all the nearby track teams. Number of members Number of teams 48 4. 66 3 82 4 101 2 104 4 107 3 X is the number of members that a randomly chosen team has. What is the expected valu X? Write your answer as a decimal.

Answer 1

We have a table that shows the records of the track coach:

Number of members Number of teams

48 4

66 3

82 4

101 2

104 4

107 3

We can read the first row as: the coach recorded 48 runners that belong to 4 teams.

To calculate the expected value of members per team we have to aggregate all the records and calculate the total number of members recorded and divide it by the total numbers of teams recorded:

`\bar{X}=\frac{\sum ^{}_{}\text{members}}{\sum ^{}_{}\text{teams}}=(48+66+82+101+104+107)/(4+3+4+2+4+3)=(508)/(20)=25.4`

Answer: the expected value for X is 25.4 members per team.