Solution: 1. The mean is given below:

Where:
 is the frequency
 is the frequency
 is the value
 is the value

 

Therefore, the mean = 2.4
2. The mean is given below:

 

 

I am not understanding why your teacher 14.3 is wrong. Please check whether the weight of 4 pumpkins is correct or not.
3. We are given that on average 5 passengers will board the bus at each of the 6 stops.
Let x be the number of passengers board the bus at the sixth stop.
Therefore, the average is:




Therefore, 7 passengers need to board the bus at the sixth stop for Leah's prediction to be true.