It is a week before the maths festival. A maths exhibitor costs £75.40 and so far 12 have been bought.
1 answer:
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<h2>Answer with explanation:</h2>
Given : A standardized exam's scores are normally distributed.
Mean test score :
Standard deviation :
Let x be the random variable that represents the scores of students .
z-score :
We know that generally , z-scores lower than -1.96 or higher than 1.96 are considered unusual .
For x= 1900
Since it lies between -1.96 and 1.96 , thus it is not unusual.
For x= 1240
Since it lies between -1.96 and 1.96 , thus it is not unusual.
For x= 2190
Since it is greater than 1.96 , thus it is unusual.
For x= 1240
Since it lies between -1.96 and 1.96 , thus it is not unusual.