# Find the variance for the given data. Round your answer to one more decimal place than the original data. 18, 20, 18, 2, 7

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The mean of the given data is (18 + 20 + 18 + 2 + 7)/5 = 13

To calculate the variance we need to find the difference between each term of the data, find the square of the value and then determine the average of the squares.

18 - 13 = 5 , 20 - 13 = 7, 18 - 13 = 5, 2 - 13 = -11 and 7 - 13 = -6.

The average of the square is:

(5^2 + 7^2 + 5^2 + 11^2 + 6^2)/5

=> (25 + 49 + 25 + 121 + 36)/5

=> 51.2

**The required variance is 51.2**

Solve the problem. Round results to the nearest hundredth.

Scores on a test have a mean of 70 and a standard deviation of 11. Michelle has a score of 48. Convert Michelle's score to a z-score. (Points: 4)

-2

22

-22

2