Question

Help me please And thank you

Answer 1

The answer is A hopes this helps :)

Answer 2

The correct option is A.

Explanation:

Sample size(n)= 196

Sample mean = 12 ug/m³

Standard deviation (s)= 3.5 ug/m³

The formula for confidence interval is

`C.I=\bar{x}\pm z^** (s)/(√(n))`

Where,
`\bar{x}` is sample mean, s is sample standard deviation, n is sample size and z* is z-score at given confidence limit.

The value of z-score at 99.7% is 3.

`C.I=12\pm 3* (3.5)/(√(196))`

`C.I=12\pm 0.75`

`C.I=[12-0.75,12+0.75]`

`C.I=[11.25,12.75]`

The required solution is 11.25 ug/m³ - 12.75 ug/m³.

Therefore the correct option is A.