For a particular diamond mine, 82% of the diamonds fail to qualify as "gemstone grade". A random sample of 90 diamonds is analysed. Find the probability that the proportion of the sample diamonds that fail to qualify as gemstone grade is between 0.78 and 0.88.
A)0.7695
B)0.1611
C)0.9306
D)0.8389

Question

Quizplus · Accepted Answer

The probability that the proportion of the sample diamonds that fail to qualify as gemstone grade is between 0.78 and 0.88 is 0.7695. This is because the probability of getting a sample proportion between 0.78 and 0.88 is given by the area under the normal curve between those two values. The area under the normal curve between 0.78 and 0.88 is 0.7695.

For a Particular Diamond Mine, 82% of the Diamonds Fail