Question

How many women must be randomly selected to estimate the mean weight of women in one age group. We want 90% confidence that the sample mean is within 2.1 lb of the population mean, and the population standard deviation is known to be 19 lb.

14) A) 445

B) 222

C) 278

D) 315

Answer 1

SOLUTION-

GIVEN, MEAN = 2.1 lbs

STANDARD DEVIATION = 19 lbs

FOR 90% CONFIDENCE INTERVAL, Z = 1.645

NOW, LET THE MINIMUM SAMPLE SIZE BE 'n'

HENCE,

OR,

OR,

ANSWER- OPTION(B)

**REMARK**- IN CASE OF DOUBT, COMMENT BELOW. ALSO LIKE THE SOLUTION, IF POSSIBLE.