Online Test — Statistics (Measures of Center & Variability)
10 Questions • 20 min • Chapter MCQ
20:00
Question 1 of 10
easy
Find the mean: {12, 15, 18, 21, 24}
15
16
18
20
Explanation: Sum = 90. Count = 5. Mean = 90/5 = 18.
Question 2 of 10
easy
Find the median: {8, 3, 11, 7, 5, 14, 9}
7
8
9
11
Explanation: Sorted: 3,5,7,8,9,11,14. Middle value (4th of 7) = 8.
Question 3 of 10
easy
Find the mode: {2,4,4,6,6,6,8,8,10}
4
6
8
4 and 6
Explanation: 6 appears 3 times (most frequent), so mode = 6.
Question 4 of 10
medium
A box plot has min=20, Q1=35, median=50, Q3=65, max=80. Find the IQR.
30
45
60
80
Explanation: IQR = Q3 - Q1 = 65 - 35 = 30.
Question 5 of 10
medium
Find the MAD (Mean Absolute Deviation) of {6, 8, 10, 12}.
2
3
4
5
Explanation: Mean=9. Distances: |6-9|=3, |8-9|=1, |10-9|=1, |12-9|=3. Sum=8. MAD=8/4=2.
Question 6 of 10
easy
Which measure is most affected by an outlier?
Median
Mode
Mean
Range
Explanation: The mean uses all values in its calculation, so extreme values (outliers) change it significantly.
Question 7 of 10
medium
A survey of 50 random students found 32 like math. Estimate the percent of all 500 students who like math.
50%
58%
64%
70%
Explanation: 32/50 = 0.64 = 64%. We infer the same proportion for the population.
Question 8 of 10
hard
Find the five-number summary of {45, 52, 38, 61, 47, 55, 49}.
38,45,49,55,61
38,47,49,52,61
38,45,47,55,61
38,47,52,55,61
Explanation: Sorted: 38,45,47,49,52,55,61. Min=38, Q1=45, Median=49, Q3=55, Max=61.
Question 9 of 10
medium
Dataset A: {10,20,30,40,50}, Dataset B: {28,29,30,31,32}. Which has larger MAD?
A
B
Same
Cannot determine
Explanation: A is spread out (MAD=12) while B is clustered (MAD ~1.2). A has much larger MAD.
Question 10 of 10
easy
A class has mean=75 and MAD=5. What does MAD=5 tell us?
Average score is 75
Scores range from 70 to 80
On average, scores are 5 units away from the mean
Median score is 75
Explanation: MAD = average distance from the mean. So on average, each score is 5 units away from 75.