Question

A standardized​ exam's scores are normally distributed. In a recent​ year, the mean test score was 21.4 and the standard deviation was 5.5. The test scores of four students selected at random are 13​, 24​, 10​, and 36. Find the​ z-scores that correspond to each value and determine whether any of the values are unusual. The​ z-score for 13 is nothing. ​(Round to two decimal places as​ needed.)

Answer 1

Answer:

-1.53

0.47

-2.07

2.65

The last two observations are unusual

Step-by-step explanation:

mathematically;

z-score =( x-mean)/SD

Kindly note that an observation is termed unusual if the z-score is greater than +2 or less than -2

for x= 13

z-score = (13-21.4)/5.5 = -1.53

for x= 24

z-score= (24-21.4)/5.5 = 0.47

for x = 10

z-score = (10-21.4)/5.5 = -2.07

unusual

for x = 36

z-score = (36-21.4)/5.5 = 2.65

unusual