Aprogrammer plans to develop a new software system. in planning for the operating system he will use, he needs to estimate the percentage of computers that use a new operating systems. how many computers must be surveyed in order to be 90% confident that his estimate is in error by no more than four percentage points? a) assume that nothing is known about the percentage of computers with new operating systems. n = ? b) assume that a recent survey suggests that 99% of computers use a new operating system. n = ?

a) 423  b) 17

Step-by-step explanation:

As per given , we have

E=4% = 0.04

Confidence level : 90%

The critical value for 90% confidence interval : z*=1.645

a) When the prior estimate of the population proportion is unknown , then the formula to find the sample size is given by :-

, where E = margin of error.

z* = Critical value.

Required sample size :  (Substitute the given values in the formula)

i.e. n= 423

b) When the prior estimate of the population proportion is known , then the formula to find the sample size is given by :-

, where p = Population proportion from prior study.

E = margin of error.

z* = Critical value.

here p= 0.99

     (Substitute the given values in the formula)

i.e. n= 17

sas (side angle side)

aa(angle angle)

sss(side side side)

sas you have to find two sides with an angle in between

aa you find two angles because it will always add up to 180

sss find all sides

step-by-step explanation: