Final answer:
There are no outliers in the data set, according to the IQR. Parts a and c of the problem do not give the same answer.
Step-by-step explanation:
The interquartile range (IQR) is calculated by finding the difference between the third quartile (Q3) and the first quartile (Q1). In this case, Q3 = 9 and Q1 = 4, so IQR = 9 - 4 = 5. To identify outliers using the IQR, we multiply the IQR by 1.5 and add it to Q3 and subtract it from Q1. This gives us a range of 11.5 to -1.5. Since there are no data points that fall outside this range, there are no outliers in the data.
Regarding parts a and c of the problem, they do not give the same answer. Part a is asking about outliers using the IQR, while part c is asking about data values that are more than two standard deviations away from the mean. These are two different methods of identifying unusual data.