Suppose a set of test scores is approximately bell-shaped, with a mean of 66 and a range of 60.

(a) The minimum test score is approximately 36 Correct: Your answer is correct. , and the maximum test score is approximately 96 Correct: Your answer is correct. .
(b) The standard deviation of the test scores is approximately

The lower limit is 36

Upper limit is 96

Standard deviation is 30

Step-by-step explanation:

Considering the range of the test score which is 60. i.e the difference between the largest and the smallest number is 60. The mean is 66 which is a measure of central tendency. That is it is at the centre of the distribution. Dividing 60 by 2 gives 30.

Adding 30 to the mean will indicate our upper limit i.e 30+66=96

Also, subtracting 30 from 66 will give the lower limit i.e. 66-30=36

The Distance between the range and the mean is the standard deviation

Which in this case is +30 or -30