Medical MCQ-The PEFR of a group of 11 year old girls follow a normal distrubution with mean 300 1/min and standard deviation 20 1/min -

The PEFR of a group of 11 year old girls follow a normal distrubution with mean 300 1/min and standard deviation 20 1/min –

About 95% of the girls have PEFR between 260 and 340 1/min.

The girls have healthy lungs

About 5% of girls have PEFR below 260 1/min.

All the PEFR must be less than 340 1/min.

Question Category:

Social & Preventive Medicine

Correct Answer:

About 95% of the girls have PEFR between 260 and 340 1/min.

Description:

1 SD includes → 68% of values 2 SD includes → 95% of values 3 SD includes → 99.7% of valuesIn this question Mean PEFR = 300 L/min SD = 2 L/minArea around 1SD on either side of mean (x ± 1SD) will include 68% of values, i.e.x± 1SD=300±20 So, 68% of girls have PEFR between 280 & 320 L/min.Area around 2SD on either side of mean (x ± 2SD) will include 95% of values, i.e.x±2SD=300±40 So, 95% of girls have PEFR between 260 & 340 L/min.Area around 3SD on either side of mean (x ± 3SD) will include 99.7% of values, i.e. -x ±3SD = 300 ± 60 So, 99.7% of girls will have PEFR between 240 & 360 L/min.

Previous MCQ

Next MCQ

Get More

Subject Mock Tests

Try practicing mock tests with over 200,000 questions from various medical subjects.

Attempt a mock test now

Mock Exam

Attempt an exam of 100 questions randomly chosen from all subjects.

Coming Soon