Igcse Model Questions Vol1 2020 Mathematics Question 4

Practice objective / multiple choice question 4 from the 2020 Igcse Model Questions Vol1 Mathematics examination.

Igcse Model Questions Vol1 2020 Mathematics Objective / Multiple Choice Hard Difficulty
Question 4 IGCSE_MODEL_QUESTIONS_VOL1 • 2020 • MATHEMATICS • objective

Class X has 20 students with a mean score of 68 and a standard deviation of 5. Class Y has 30 students with a mean score of 75 and a standard deviation of 8. Assuming the scores are independent, (a) find the mean and standard deviation of the combined 50 students, and (b) determine the \(z\)-score of a student who scored 85 in the combined set.

Answer Options

A. Mean = 70.8, SD ≈ 6.9; z‑score ≈ 2.10
B. Mean = 73.0, SD ≈ 8.0; z‑score ≈ 1.25
Correct Answer C. Mean = 72.2, SD ≈ 7.72; z‑score ≈ 1.66
D. Mean = 71.5, SD ≈ 7.5; z‑score ≈ 1.73
Correct Answer
C
Correct Option:
Mean = 72.2, SD ≈ 7.72; z‑score ≈ 1.66

About This Question

This is Igcse Model Questions Vol1 2020 Mathematics Question 4. It is one of the objective questions from the 2020 Igcse Model Questions Vol1 Mathematics examination.

Difficulty level: Hard .

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