A population is estimated to have a standard deviation of 9. We want to estimate the population mean within 2, with a 99% level of confidence. How large a sample is required? (Round up your answer to the next whole number.)

The sample required is  

Step-by-step explanation:

From the question we are told that

     The  standard deviation is  

      The margin of error is

Given that the confidence level is  99%  then the level of  significance is mathematically evaluated as

Next we will obtain the critical value   from the normal distribution table(reference  math dot armstrong dot edu) , the value is  

The  sample size is mathematically represented as

substituting values

this is false ^.^ lol

c.

step-by-step explanation:

she should of added 9^2 and 12^2. that is because it is a^2+b^2=c^2. c^2 is the hypotenuse and should always be bigger than the other two numbers. which is why she should of added 9 squared and 12 squared together instead of 15 squared.