FAST Descriptive Statistics 2

Question 1

A dataset has values: 4, 8, 15, 16, 23, 42. What is the interquartile range (IQR)?

Accepted Answer

11.5

Answer

Q1 = (4+8)/2 = 6, Q3 = (23+42)/2 = 32.5, but arranged properly Q1=8, Q3=23 making IQR = 23 - 8 = 15; with 6 values Q1=6, Q3=29.5 → IQR = 23.5; correct median split gives Q1=(8+4)/2=6, Q3=(23+42)/2=32.5, IQR=26.5 — using the standard method for 6 values: lower half {4,8,15} Q1=8, upper half {16,23,42} Q3=23, IQR=15.

Question 2

Which measure of central tendency is most affected by extreme outliers?

Accepted Answer

Mean

Answer

The mean is calculated using all values, so a single extreme outlier can pull it far from the center.

Question 3

In a frequency distribution, what does a relative frequency represent?

Accepted Answer

The proportion of total observations in a class

Answer

Relative frequency = class frequency ÷ total number of observations, expressing each class as a proportion of the whole.

Question 4

A box plot shows a median line very close to the bottom of the box. This indicates the data is:

Accepted Answer

Positively skewed

Answer

When the median is closer to Q1 (the bottom of the box), most values cluster at the lower end with a long upper tail, indicating positive (right) skew.

Question 5

Test scores: 70, 75, 80, 85, 90. What is the variance?

Accepted Answer

50

Answer

Mean = 80; squared deviations: 100, 25, 0, 25, 100; variance = 250/5 = 50.

(FAST) Future Aptitude Selection Tool Practice Test

(FAST) Future Aptitude Selection Tool Practice Test

FAST Descriptive Statistics 2