Answer:
the 90th percentile is 145
Step-by-step explanation:
Data provided:
152 121 130 143 122 101 137 98 138 127 145 117
Number of students considered, n = 12
To find:
90th percentile
Now,
Step 1 : Arrange the data in ascending order
98, 101, 117, 121, 122, 127, 130, 137, 138, 143, 145, 152
Step 2 : Compute the position of the 90th percentile
position of the 90th percentile, i = (90% × n)
Thus,
i = 0.90 × 12
or
i = 10.8
Now,
Step 3 : Since, the index i is not an integer, round up to the nearest integer
i.e i = 11
Therefore,
The 90th percentile is the value in 11th position,
i.e 145
