Civil Service Numerical Reasoning Test Statistical Reasoning 2

Question 1

A dataset shows annual staff turnover rates for 8 years: 5.2%, 6.1%, 4.8%, 7.3%, 5.5%, 6.8%, 5.0%, 6.3%. What is the interquartile range (IQR)?

Accepted Answer

1.45 percentage points

Answer

1.80 percentage points

Answer

1.10 percentage points

Answer

2.00 percentage points

Question 2

A correlation coefficient of r = -0.82 is found between staff absence rates and team productivity scores. Which statement best describes this relationship?

Accepted Answer

Strong negative correlation: as absence rises, productivity falls

Answer

Strong positive correlation: as absence rises, productivity rises

Answer

Weak negative correlation: little relationship exists

Answer

No meaningful correlation exists

Question 3

A policy proposal is tested with two groups. Group A (n=200) shows a 15% improvement. Group B (n=800) shows a 3% improvement. What is the overall weighted improvement across both groups?

Accepted Answer

5.4%

Answer

9.0%

Answer

6.0%

Answer

7.2%

Question 4

A moving average of quarterly benefit claims uses a 4-quarter window. The claims (in thousands) are: Q1: 320, Q2: 345, Q3: 380, Q4: 310, Q5: 355. What is the 4-quarter moving average for the period Q1 to Q4?

Accepted Answer

338.75

Answer

342.50

Answer

351.25

Answer

346.00

Question 5

A department's error rate follows a Poisson distribution with a mean of 3 errors per day. What is the probability of exactly 0 errors on a given day? (Use e to the power of -3 = 0.0498)

Accepted Answer

4.98%

Answer

3.00%

Answer

6.72%

Answer

5.50%

Question 6

A time series shows seasonal indices for passport applications: Spring 1.15, Summer 1.30, Autumn 0.85, Winter 0.70. The deseasonalised figure for Summer is 450,000. What is the actual (raw) figure?

Accepted Answer

585,000

Answer

525,000

Answer

615,000

Answer

550,000