Q.Based on a sample of size 20, the mean
value is 31.5. If two more observations,
35 and 39, are added to the sample, then
the new mean is
(1) 35.167
(2) 32
(3) 35.2
(4) 29.5
Answers
Answer:
The new mean of sample of 20 observations that has a mean of 31.5 and two observations 35 and 39 are added, is 32
Explanation:
Mean,also known as average, is the total sum or value of elements in a data set divided by the number of the elements the data set.
Mean = total sum of elements / total number of elements
∴ Total sum of elements = total number of elements × Mean
In this case we have a mean of 31.5 with a total number of 20 observations.
∴ Total sum of the elements = 31.5 × 20
= 630
We can now calculate the new mean by factoring the newly added observations; 35 and 39
The total of 35 and 39 = 74
The new total sum of all the observation therefore = 630 + 74 = 704
The new total number of elements = 20 + 2 ( 35 and 39 have been added)
= 22
New mean = new total sum of elements / new number of elements
= 704/ 22
= 32
Therefore the new mean = 32
Answer:32
Explanation: