The mean of five numbers is . A sixth number, , is added. What is the mean of all six numbers?
Answer and explanation
Correct answer: A.
- Step 1: Original total .
- Step 2: New total over numbers.
- Step 3: New mean .
Answer
.
Why not the others: : averages the old mean with the new number . : divides the new total of by instead of . : gives the new total and forgets to divide.
Practise more Statistics.
Free questions with an explanation for every one, and full timed ESAT (Engineering and Science Admissions Test) mock tests.
More Statistics questions
- The data set is split into halves by excluding the median. What is the interquartile range?
- In a histogram, the bar for the class has height on the frequency density axis. How many items are in that class?
- A frequency table shows the scores with frequencies . What is the median score?
- Every value in a data set is multiplied by and then is added. The original mean is and the original standard deviation is . W…