Waec Model Questions Vol1 2021 Mathematics Question 5

Practice objective / multiple choice question 5 from the 2021 Waec Model Questions Vol1 Mathematics examination.

Waec Model Questions Vol1 2021 Mathematics Objective / Multiple Choice Hard Difficulty
Question 5 WAEC_MODEL_QUESTIONS_VOL1 • 2021 • MATHEMATICS • objective

A class of 30 students took a test. Their mean score was 68 and the standard deviation was 6. Later, 5 absent students took a make‑up test and scored 80, 85, 78, 90 and 82. Assuming the original 30 scores remain unchanged, what are the new mean and the new standard deviation of the 35 scores? Give the mean to two decimal places and the standard deviation to two decimal places.

Answer Options

A. Mean = 70.14, SD = 8.12
Correct Answer B. Mean = 70.14, SD = 7.80
C. Mean = 69.85, SD = 7.55
D. Mean = 71.23, SD = 7.80
Correct Answer
B
Correct Option:
Mean = 70.14, SD = 7.80

About This Question

This is Waec Model Questions Vol1 2021 Mathematics Question 5. It is one of the objective questions from the 2021 Waec Model Questions Vol1 Mathematics examination.

Difficulty level: Hard .

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