Question

19. The mean of the dataset is 18. What number is missing? 21, 11, 27, 13, 16​

Answer 1

missing number is 20

Explanation:

the mean of a dataset is calculated as

mean =
`(sum)/(count)`

let x be the missing number , then dataset is

21 , 11 , 27 , 13 , 16 , x

sum = 21 + 11 + 27 + 13 + 16 + x = 88 + x

count = 6 ( that is number of values in the data set )

given mean = 18 , then

`(88+x)/(6)` = 18 ( multiply both sides by 6 )

88 + x = 108 ( subtract 88 from both sides )

x = 20

the missing number is 20

Answer 2

`\Huge \boxed{\boxed{\bf{20}}}`

Explanation:

The mean (average) of a dataset is the sum of all the numbers in the dataset, which is then divided by the total values in the dataset.

Here, the mean of the dataset is 18, and there are 6 numbers in the dataset (including the missing number). So, the sum of all the numbers in the dataset should be:

`\LARGE \boxed{\tt{18 * 6 = 108}}`

The sum of the given numbers in the dataset is:

`\LARGE \boxed{\tt{21 + 11 + 27 + 13 + 16 = 88}}`

To find the missing number, subtract the sum of the given numbers from the total sum:

`\LARGE \boxed{\tt{108 - 88 = 20}}`

So, the missing number in the dataset is 20. Therefore, the full and completed dataset will be 21, 11, 27, 13, 16, 20.

#BTH1

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