Question

4. If a random sample of 50 cups of soda dispensed from a machine showed the mean amount of soda dispensed was 7.9 ounces with s=0.35 ounces, find the confidence level if the margin of error is 0.083.
5. Suppose that a random sample of 25 mining caps was tested from a population of 300 mining caps and 20 exploded properly.

Answer 1

CI =X̄ ± Z×s/$\sqrt n$ =7.9 ± 0.083

Z×s/$\sqrt n$ =Z×( 0.35$/\sqrt {50}$ )=0.083

Z=1.64, using table, confidence level=90%