CA Foundation P3 · Chapter 14 · Question 9 of 10
The standard deviation of x is 5. If y = 3 − 2x, the standard deviation of y is:
Test yourself: pick an answer
Reveal answer & explanation
Correct answer: A) 10
Explanation
Standard deviation is unaffected by change of origin but affected by change of scale in absolute value: SD(y) = |−2| x SD(x) = 2 x 5 = 10. SD can never be negative, so −10 is impossible.
More Measures of Central Tendency and Dispersion MCQs
- Q1A student scores 60, 75 and 80 in three papers carrying weights 2, 3 and 5 respectively. The weighted mean score is:
- Q2The median of 23, 11, 37, 19, 42, 28 is:
- Q3In a moderately skewed distribution, the mean is 42 and the median is 40. Using the empirical relationship, the mode is approximately:
- Q4For the distribution below, the median is (to two decimals): Class: 0–10, 10–20, 20–30, 30–40, 40–50 Frequency: 5, 8, 12, 10, 5
- Q5For the distribution below, the mode is (to two decimals): Class: 0–10, 10–20, 20–30, 30–40, 40–50 Frequency: 5, 8, 12, 10, 5