Mathematical Methods — Question 3

QCAA 2023, Paper 2 · 1 mark

Q3 · 2023 · Technology-activeSimple familiar1 mark

QUESTION 3

A normal distribution has 95% of values approximately between

50.32

and

113.68

, with mean

82

. Its standard deviation is closest to

(A)

16.16

(B)

21.12

(C)

31.68

(D)

63.36

ABCD

WORKED SOLUTION

1 mark

ANSWER

A —

16.16

Worked solution

Half-width is

31.68\approx1.96\sigma

, so

\sigma\approx16.16

; A.

Selects option A.

[1 mark]

Worked explanation by QCE Vault; correct option verified against the QCAA answer key.