An engineer wishes to determine the width of a particular electronic component. If she knows that the standard deviation of all components is 2.2 mm, how many of these components should she consider to be 80% sure of know the mean will be within 0.3 mm?

So the answer for this case would be n=16 rounded up to the nearest integer

Step-by-step explanation:

For this case we have the following info given:

represent the population deviation

represent the margin of error desired

The margin of error for the true mean is given by this formula:

   (a)

And on this case we have that ME =0.03 and we are interested in order to find the value of n, if we solve n from equation (a) we got:

  (b)

The confidence level is 80%, the significance would be and the critical value for this case is , replacing into formula (b) we got:

So the answer for this case would be n=16 rounded up to the nearest integer

an = 22 + (n-1) *6

110 seats

step-by-step explanation:

an=a1+(n-1)(d)

a1 = 22   this is the first item in the sequence

d =6   this is how the sequence goes up

a)   an = 22 + (n-1) *6

b) a12 = 22 + (12-1) *6

    a12 = 22+11*6

  a12 = 22 +88

  a12 = 110