1. An election poll reported that candidate had approval rating 31% with margin of error E of 4%. Construct a confidence interval for proportion of adults who approved of the candidate.    

The confidence interval is ......

2. A machine cuts plastic in sheets which are 40 feet (480 inches. Assume that the population of lengths is normally distributed. Complete parts (a) and (b)

a) The company wants to estimates the mean length the machine is cutting plastiv in 0.5 inche. Determine the minimum sample size needed to make a 95% confidence interval for population mean. Assume the population standard deviation is 1 inch

n=........

b) Repeat par(a) using the error tolerance of 0.25 inch

n=.......  

Which error tolerance needs a larger sample size? Describe

a. The tolerance E = 0.25 inch needs a larger sample size. As error size decreases, large sample should be taken to make sure the desired accuracy.

b. The tolerance E = 0.25 inch needs a larger sample size. As error size raises, a large sample should be taken to make sure the desired accuracy.

c. The tolerance E = 0.5 inch needs a larger sample size. As error size raises, a large sample should be taken to make sure the desired accuracy.  

d. The tolerance E = 0.5 inch needs a larger sample size. As error size reduces, a large sample should be taken to make sure the desired accuracy.